Death by Tylenol

In 1982, two firefighters from a Chicago suburb were casually discussing four bizarre deaths that had recently taken place in a neighboring area. As they discussed the circumstances of the deaths, they realized that each of the victims had taken Tylenol. Their suspicions were immediately reported to police investigators. Tragically, before the general public could be alerted, three more victims died after taking poison- laced Tylenol capsules. Seven individuals, all in the Chicago area, were the first victims to die from what has become known as product tampering. A forensic chemical analysis of Tylenol capsules recovered from the victims’ residences showed that the capsules were filled with potassium cyanide in a quantity ten thousand times what was needed to kill an average person. It was quickly determined that the

cyanide was not introduced into the bottles at the factory. Instead, the perpetrator methodically

emptied each of twenty to thirty capsules and then refilled them with potassium cyanide. The tampered capsules were rebottled, carefully repackaged,

and placed on the shelves of six different stores. The case of the Tylenol murders remains unsolved, and the $100,000 reward offered by Tylenol’s manufacturer remains unclaimed.

headline news

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After studying this chapter you should be able to: • Define and distinguish elements and compounds

• Contrast the differences among a solid, liquid, and gas

• Define and distinguish organic and inorganic compounds

• Understand the difference between qualitative and quantitative analysis

• Describe and explain the process of chromatography

• List and describe the parts of a gas chromatograph

• Explain the differences among thin-layer chromatography, gas chromatography, and electrophoresis

• Understand the differences between the wave and particle theories of light

• Describe the electromagnetic spectrum

• Name the parts of a simple absorption spectrophotometer

• Describe the utility of ultraviolet and infrared spectroscopy for the identification of organic compounds

• Describe the concept and utility of mass spectrometry for identification analysis

organic analysis

chromatography compound electromagnetic

spectrum electrophoresis element fluoresce frequency gas (vapor) infrared inorganic ion laser liquid matter monochromatic light monochromator organic periodic table phase photon physical state pyrolysis solid spectrophotometry sublimation ultraviolet visible light wavelength X-ray

KEY TERMS

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gas (vapor) A state of matter in which the attractive forces between molecules are small enough to permit them to move with complete freedom

liquid A state of matter in which molecules are in contact with one another but are not rigidly held in place

solid A state of matter in which the molecules are held closely together in a rigid state

physical state A condition or stage in the form of matter; a solid, liquid, or gas

compound A pure substance composed of two or more elements

element A fundamental particle of matter; an element cannot be broken down into simpler substances by chemical means

matter All things of substance; matter is composed of atoms or molecules

120 CHAPTER 5

The Nature of Matter In the previous chapter, some physical properties were described and used to characterize glass and soil evidence. Before we can apply other physical properties, as well as chemical properties, to the identification and comparison of evidence, we need to gain an insight into the composition of matter. Beginning with knowledge of the fundamental building block of all substances—the element—it will be convenient for us to classify all evidence as either organic or inorganic. The procedures used to measure the properties associated with each class are distinctly different and merit separate chapters for their description. In later chapters, we will continually return to these procedures as we discuss the examination of the various kinds of physical evidence. This chap- ter will be devoted, in large part, to reviewing a variety of techniques and instruments that have become the indispensable tools of the forensic scientist for examining organic evidence.

Elements and Compounds Matter is anything that has mass and occupies space. As we examine the world that surrounds us and consider the countless variety of materials that we encounter, we must consider one of humankind’s most remarkable accomplishments: the discovery of the concept of the atom to explain the composition of all matter. This search had its earliest contribution from the ancient Greek philosophers, who suggested air, water, fire, and earth as matter’s fundamental building blocks. It culminated with the development of the atomic theory and the discovery of matter’s simplest identity, the element.

An element is the simplest substance known and provides the building block from which all matter is composed. At present, 118 elements have been identified (see Table 5–1); of these, 89 occur naturally on the earth, and the remainder have been created in the laboratory. In Figure 5–1, all of the elements are listed by name and symbol in a form that has become known as the periodic table. This table is most useful to chemists because it systematically arranges elements with similar chemical properties in the same vertical row or group.

For convenience, chemists have chosen letter symbols to represent the elements. Many of these symbols come from the first letter of the element’s English name—for example, carbon (C), hydrogen (H), and oxygen (O). Others are two-letter abbreviations of the English name—for example, calcium (Ca) and zinc (Zn). Some symbols are derived from the first letters of Latin or Greek names. Thus, the symbol for silver, Ag, comes from the Latin name argentum; copper, Cu, from the Latin cuprum; and helium, He, from the Greek name helios.

The smallest particle of an element that can exist and still retain its identity as that element is the atom. When we write the symbol C we mean one atom of carbon; the chemical symbol for carbon dioxide, CO2, signifies one atom of carbon combined with two atoms of oxygen. When two or more elements are combined to form a substance, as with carbon dioxide, a new substance is created, different in its physical and chemical properties from its elemental components. This new material is called a compound. Compounds contain at least two elements. Considering that there are eighty-nine natural elements, it is easy to imagine the large number of possible elemental combinations that may form compounds. Not surprisingly, more than 16 million known compounds have already been identified.

Just as the atom is the basic particle of an element, the molecule is the smallest unit of a com- pound. Thus, a molecule of carbon dioxide is represented by the symbol CO2, and a molecule of table salt is symbolized by NaCl, representing the combination of one atom of the element sodium (Na) with one atom of the element chlorine (Cl).

States of Matter As we look around us and view the materials that make up the earth, it becomes an awesome task even to attempt to estimate the number of different kinds of matter that exist. A much more logical approach is to classify matter according to the physical form it takes. These forms are called physical states. There are three such states: solid, liquid, and gas (vapor). A solid is rigid and therefore has a definite shape and volume. A liquid also occupies a specific volume, but its fluidity causes it to take the shape of the container in which it is residing. A gas has neither a definite shape nor volume, and it will completely fill any container into which it is placed.

periodic table A chart of elements arranged in a systematic fashion; vertical rows are called groups or families, and horizontal rows are called series; elements in a given row have similar properties

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ORGANIC ANALYSIS 121

TABLE 5–1 List of Elements with Their Symbols and Atomic Masses

Element Symbol Atomic Massa (amu)

Lead Pb 207.2 Lithium Li 6.941 Lutetium Lu 174.97 Magnesium Mg 24.305 Manganese Mn 54.9380 Meitnerium Mt (266) Mendelevium Md (256) Mercury Hg 200.59 Molybdenum Mo 95.94 Neodymium Nd 144.24 Neon Ne 20.179 Neptunium Np 237.0482 Nickel Ni 58.71 Niobium Nb 92.9064 Nitrogen N 14.0067 Nobelium No (254) Osmium Os 190.2 Oxygen O 15.9994 Palladium Pd 106.4 Phosphorus P 30.9738 Platinum Pt 195.09 Plutonium Pu (244) Polonium Po (209) Potassium K 39.102 Praseodymium Pr 140.9077 Promethium Pm (145) Protactinium Pa 231.0359 Radium Ra 226.0254 Radon Rn (222) Rhenium Re 186.2 Rhodium Rh 102.9055 Roentgenium Rg (272) Rubidium Rb 85.4678 Ruthenium Ru 101.07 Rutherfordium Rf (257) Samarium Sm 105.4 Scandium Sc 44.9559 Seaborgium Sg (263) Selenium Se 78.96 Silicon Si 28.086 Silver Ag 107.868 Sodium Na 22.9898 Strontium Sr 87.62 Sulfur S 32.06 Tantalum Ta 180.9479 Technetium Tc 98.9062 Tellurium Te 127.60 Terbium Tb 158.9254 Thallium Tl 204.37 Thorium Th 232.0381 Thulium Tm 168.9342

Element Symbol Atomic Massa (amu)

Actinum Ac (227) Aluminum Al 26.9815 Americium Am (243) Antimony Sb 121.75 Argon Ar 39.948 Arsenic As 74.9216 Astatine At (210) Barium Ba 137.34 Berkelium Bk (247) Beryllium Be 9.01218 Bismuth Bi 208.9806 Bohrium Bh (262) Boron B 10.81 Bromine Br 79.904 Cadmium Cd 112.40 Calcium Ca 40.08 Californium Cf (251) Carbon C 12.011 Cerium Ce 140.12 Cesium Cs 132.9055 Chlorine Cl 35.453 Chromium Cr 51.996 Cobalt Co 58.9332 Copernicium Cp (285) Copper Cu 63.546 Curium Cm (247) Darmstadtium Ds (271) Dubnium Db (260) Dysprosium Dy 162.50 Einsteinium Es (254) Erbium Er 167.26 Europium Eu 151.96 Fermium Fm (253) Fluorine F 18.9984 Francium Fr (223) Gadolinium Gd 157.25 Gallium Ga 69.72 Germanium Ge 72.59 Gold Au 196.9665 Hafnium Hf 178.49 Hassium Hs (265) Helium He 4.00260 Holmium Ho 164.9303 Hydrogen H 1.0080 Indium In 114.82 Iodine I 126.9045 Iridium Ir 192.22 Iron Fe 55.847 Krypton Kr 83.80 Lanthanum La 138.9055 Lawrencium Lr (257)

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sublimation A physical change from the solid state directly into the gaseous state

122 CHAPTER 5

CHANGES OF STATE Substances can change from one state to another. For example, as water is heated, it is converted from a liquid form into a vapor. At a high enough temperature (100°C), water boils and rapidly changes into steam. Similarly, at 0°C, water solidifies or freezes into ice. Under certain conditions, some solids can be converted directly into a gaseous state. For instance, a piece of dry ice (solid carbon dioxide) left standing at room temperature quickly forms carbon dioxide vapor and disappears. This change of state from a solid to a gas is called sublimation.

In each of these examples, no new chemical species are formed; matter is simply being changed from one physical state to another. Water, whether in the form of liquid, ice, or steam, remains chemically H2O. Simply, what has been altered are the attractive forces between the water molecules. In a solid, these forces are very strong, and the molecules are held closely to- gether in a rigid state. In a liquid, the attractive forces are not as strong, and the molecules have more mobility. Finally, in the vapor state, appreciable attractive forces no longer exist among the molecules; thus, they may move in any direction at will.

1 H

3 Li

11 Na

19 K

37 Rb

55 Cs

87 Fr

4 Be

12 Mg

20 Ca

38 Sr

56 Ba

88 Ra

IIIB

39 Y

57 La

89 Ac

IVB

40 Zr

72 Hf

104 Rf

VB

41 Nb

73 Ta

105 Db

VIB

42 Mo

74 W

106 Sg

VIIB

43 Tc

75 Re

107 Bh

44 Ru

76 Os

108 Hs

VIII

45 Rh

77 Ir

109 Mt

46 Pd

78 Pt

110 Ps

IB

47 Ag

79 Au

111 Rg

IIB

48 Cd

80 Hg

112 Cp

5 B

13 Al

IIIA

49 In

81 Tl

113 Uut

6 C

14 Si

IVA

50 Sn

82 Pb

114 Uuq

7 N

15 P

VA

51 Sb

83 Bi

115 Uup

8 O

16 S

VIA

52 Te

84 Po

116 Uuh

9 F

17 Cl

VIIA

53 I

85 At

117 Uus

2 He

10 Ne

18 Ar

O

54 Xe

21 Sc

22 Ti

23 V

24 Cr

25 Mn

26 Fe

27 Co

28 Ni

29 Cu

30 Zn

31 Ga

32 Ge

33 As

34 Se

35 Br

36 Kr

86 Rn

118 Uuo

58 Ce

90 Th

59 Pr

91 Pa

60 Nd

92 U

61 Pm

93 Np

62 Sm

94 Pu

63 Eu

95 Am

64 Gd

96 Cm

65 Tb

97 Bk

66 Dy

98 Cf

67 Ho

99 Es

68 Er

100 Fm

69 Tm

101 Md

70 Yb

102 No

71 Lu

103 Lr

1

2

3

4

5

6

7

a

b

aLanthanide series

bActinide series

Period IA IIA Group

FIGURE 5–1 The periodic table.

TABLE 5–1 Continued

Element Symbol Atomic Massa (amu)

Tin Sn 118.69 Titanium Ti 47.90 Tungsten W 183.85 Copernicium Cp (292) Ununoctium Uuo (294) Ununpentium Uup (288) Ununquadium Uuq (289) Ununseptium Uus (?)

Element Symbol Atomic Massa (amu)

Ununtrium Uut (284) Uranium U 238.029 Vanadium V 50.9414 Xenon Xe 131.3 Ytterbium Yb 173.04 Yttrium Y 88.9059 Zinc Zn 65.57 Zirconium Zr 91.22

aBased on the assigned relative atomic mass of C � exactly 12; parentheses denote the mass number of the isotope with the longest half-life.

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inorganic Describes a chemical compound not based on carbon

organic Describes a substance composed of carbon and often smaller amounts of hydrogen, oxygen, nitrogen, chlorine, phosphorus, or other elements

ORGANIC ANALYSIS 123

PHASES Chemists are forever combining different substances, no matter whether they are in the solid, liquid, or gaseous states, hoping to create new and useful products. Our everyday observa- tions should make it apparent that not all attempts at mixing matter can be productive. For instance, oil spills demonstrate that oil and water do not mix. Whenever substances can be distinguished by a visible boundary, different phases are said to exist. Thus, oil floating on water is an example of a two-phase system. The oil and water each constitute a separate liquid phase, clearly distinct from each other. Similarly, when sugar is first added to water, it does not dissolve, and two distinctly different phases exist: the solid sugar and the liquid water. However, after stirring, all the sugar dissolves, leaving just one liquid phase.

Selecting an Analytical Technique Now that the basic components of matter have been defined, proper selection of analytical tech- niques that enable the forensic scientist to identify or compare matter can best be understood by categorizing all substances into one of two broad groups: organics and inorganics.

Organic vs. Inorganic Substances Organic substances contain carbon, commonly in combination with hydrogen, oxygen, nitrogen, chlorine, phosphorus, or other elements. Inorganic substances encompass all other known chem- ical substances. Each of these two broad groups has distinctive and characteristic properties. Thus, once the analyst has determined whether a material is organic or inorganic, the properties to be measured and the choice of analytical techniques to be used are generally the same for all materials in each group.

Most evidence received by crime laboratories requires identification of organic compounds. These compounds may include substances such as commonly abused drugs (such as alcohol, marijuana, heroin, amphetamines, and barbiturates), synthetic fibers, petroleum products, paint binders, and high-order explosives. As we have already observed, organic compounds are composed of a combination of a relatively small number of elements that must include carbon; fortunately, the nature of the forces or bonds between these elements is such that the resultant compounds can readily be characterized by their absorption of light.

The study of the absorption of light by chemical substances, known as spectrophotometry, is a basic tool for the characterization and identification of organic materials. Although spectrophotome- try is most applicable to organic analysis, its optimal use requires that a material be in a relatively pure state. Because the purity of physical evidence is almost always beyond the control of the crim- inalist, this criterion often is not met. For this reason, the analytical technique of chromatography is widely applied for the analysis of physical evidence. Chromatography is a means of separating and tentatively identifying the components of a mixture. We will discuss both techniques in this chapter.

Qualitative vs. Quantitative Measurement Another consideration in selecting an analytical technique is the need for either a qualitative or a quantitative determination. The former relates just to the identity of the material, whereas the lat- ter refers to the percentage combination of the components of a mixture. Hence, a qualitative identification of a powder may reveal the presence of heroin and quinine, whereas a quantitative analysis may conclude the presence of 10 percent heroin and 90 percent quinine. Obviously, a qualitative identification must precede any attempt at quantitation, for little value is served by attempting to quantitate a material without first determining its identity. Essentially, a qualitative analysis of a material requires the determination of numerous properties using a variety of ana- lytical techniques. On the other hand, a quantitative measurement is usually accomplished by the precise measurement of a single property of the material.

Chromatography Chromatography as a technique for separating the components of a mixture is particularly useful for analyzing the multicomponent specimens that are frequently received in the crime laboratory. For example, illicit drugs sold on the street are not manufactured to meet government labeling standards; instead, they may be diluted with practically any material at the disposal of the drug

chromatography Any of several analytical techniques for separating organic mixtures into their components by attraction to a stationary phase while being propelled by a moving phase

spectrophotometry An analytical method for identifying a substance by its selective absorption of different wavelengths of light

phase A uniform body of matter; different phases are separated by definite visible boundaries

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124 CHAPTER 5

dealer to increase the quantity of product available to prospective customers. Hence, the task of identifying an illicit-drug preparation would be arduous without the aid of chro- matographic methods to first separate the mixture into its components.

Theory of Chromatography The theory of chromatography is based on the observation that chemical substances tend to partially escape into the surrounding environment when dissolved in a liquid or when absorbed on a solid surface. This is best illustrated by a gas dissolved in a beaker of water kept at a constant temperature. It will be convenient for us to characterize the water in the beaker as the liquid phase and the air above it as the gas phase. If the beaker is covered with a bell jar, as shown in Figure 5–2, some of the gas molecules (represented by the green balls) escape from the water into the surrounding enclosed air. The molecules that remain are said to be in the liquid phase; the molecules that have escaped into the air are said to be in the gas phase. As the gas molecules escape into the surrounding air, they accumulate above the water; here, random motion carries some of them back into the water. Eventually, a point is reached at which the number of molecules leaving the water is equal to the number returning. At this time, the liquid and gas phases are in equilibrium. If the temperature of the water is increased, the equilibrium state readjusts itself to a point at which more gas molecules move into the gas phase.

This behavior was first observed in 1803 by a British chemist, William Henry. His explanation of this phenomenon, known appropriately as Henry’s law, may be stated as follows: When a volatile chemical compound is dissolved in a liquid and is brought to equi- librium with air, there is a fixed ratio between the concentration of the volatile compound in air and its concentration in the liquid, and this ratio remains constant for a given temperature.

The distribution or partitioning of a gas between the liquid and gas phases is determined by the solubility of the gas in the liquid. The higher its solubility, the greater the tendency of the gas molecules to remain in the liquid phase. If two different gases are simultaneously dissolved in the same liquid, each will reach a state of equilibrium with the surrounding air independently of the other. For example, as shown in Figure 5–3, gas A (green balls) and gas B (blue balls) are both dissolved in water. At equilibrium, gas A has a greater number of molecules dissolved in the water than does gas B. This is so because

gas A is more soluble in water than gas B.

Basic Chromatographic Process Now return to the concept of chromatography. In Figures 5–2 and 5–3, both phases—liquid and gas—were kept stationary; that is, they were not moving. During a chromatographic process, this is not the case; instead, one phase is always made to move continuously in one direction over a stationary or fixed phase. For example, in Figure 5–3, showing the two gases represented by blue and green balls dissolved in water, chromatography will occur only when the air is forced to move continuously in one direction over the water. Because gas B has a greater percentage of its mol- ecules in the moving gas phase than does gas A, its molecules will travel over the liquid at a faster pace than those of gas A. Eventually, when the moving phase has advanced a reasonable distance, gas B will become entirely separated from gas A and the chromatographic process will be com- plete. This process is illustrated in Figure 5–4.

Simply, we can think of chromatography as being analogous to a race between chemical compounds. At the starting line, all the participating substances are mixed together; however, as the race progresses, materials that prefer the moving phase slowly pull ahead of those that prefer to remain in the stationary phase. Finally, at the end of the race, all the participants are separated, each crossing the finish line at different times.

The different types of chromatographic systems are as varied as the number of stationary and moving-phase combinations that can be devised. However, three chromatographic processes—gas chromatography, high-performance liquid chromatography, and thin-layer chromatography—are most applicable for solving many analytical problems in the crime laboratory.

Gas Chromatography (GC) Gas chromatography (GC) separates mixtures on the basis of their distribution between a sta- tionary liquid phase and a moving gas phase. This technique is widely used because of its ability to resolve a highly complex mixture into its components, usually within minutes.

FIGURE 5–2 Evaporation of a liquid.

FIGURE 5–3 At equilibrium, there are more gas A molecules (green balls) than gas B molecules (blue balls) in the liquid phase.

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ORGANIC ANALYSIS 125

BASIC THEORY OF GC In gas chromatography, the moving phase is actually a gas called the carrier gas, which flows through a column constructed of stainless steel or glass. The stationary phase is a thin film of liquid within the column. Two types of columns are used: the packed column and the capillary column. With the packed column, the stationary phase is a thin film of liquid that is fixed onto small granular particles packed into the column. This column is usually constructed of stainless steel or glass and is 2 to 6 meters long and about 3 millimeters in diame- ter. Capillary columns are composed of glass and are much longer than packed columns—15 to 60 meters long. These types of columns are very narrow, ranging from 0.25 to 0.75 millimeter in diameter. Capillary columns can be made narrower than packed columns because their stationary liquid phase is actually coated as a very thin film directly onto the column’s inner wall. In any case, as the carrier gas flows through the packed or capillary column, it carries with it the com- ponents of a mixture that have been injected into the column. Components with a greater affinity for the moving gas phase travel through the column more quickly than those with a greater affin- ity for the stationary liquid phase. Eventually, after the mixture has traversed the length of the column, it emerges separated into its components.

THE GC PROCESS A simplified scheme of the gas chromatograph is shown in Figure 5–5. The operation of the instrument can be summed up briefly as follows: A gas stream, the so-called carrier gas, is fed into the column at a constant rate. The carrier gas is chemically inert and is generally nitrogen or helium. The sample under investigation is injected as a liquid into a heated injection port with a syringe, where it is immediately vaporized and swept into the column by the carrier gas. The column itself is heated in an oven in order to keep the sample in a vapor state as it travels through the column. In the column, the components of the sample travel in the direction of the carrier gas flow at speeds that are determined by their distribution between the stationary and moving phases. If the analyst has selected the proper liquid phase and has made the column long enough, the components of the sample will be completely separated as they emerge from the column.

Liquid phase

Liquid phase

Direction of moving air

Stationary liquid phase

Direction of moving air

Stationary liquid phase

Direction of moving air

Stationary liquid phase

(a)

(b)

(c)

FIGURE 5–4 In this illustration of chromatography, the molecules represented by the blue balls have a greater affinity for the upper phase and hence will be pushed along at a faster rate by the moving air. Eventually, the two sets of molecules will separate from each other, completing the chromatographic process.

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126 CHAPTER 5

1

3

2

4

56

7 8

1. Sample

2. Injector

3. Carrier gas

4. Column

5. Detector

6. Power supply

7. Recorder

8. Chromatogram

FIGURE 5–5 Basic gas chromatography. Gas chromatography permits rapid separation of complex mixtures into individual compounds and allows identification and quantitative determination of each compound. As shown, a sample is introduced by a syringe (1) into a heated injection chamber (2). A constant stream of nitrogen gas (3) flows through the injector, carrying the sample into the column (4), which contains a thin film of liquid. The sample is separated in the column, and the carrier gas and separated components emerge from the column and enter the detector (5). Signals developed by the detector activate the recorder (7), which makes a permanent record of the separation by tracing a series of peaks on the chromatograph (8). The time of elution identifies the component present, and the peak area identifies the concentration. Courtesy Varian Inc., Palo Alto, Calif.

As each component emerges from the column, it enters a detector. One type of detector uses a flame to ionize the emerging chemical substance, thus generating an electrical signal. The signal is recorded onto a strip-chart recorder as a function of time. This written record of the separation is called a chromatogram. A gas chromatogram is a plot of the recorder response (vertical axis) versus time (horizontal axis). A typical chromatogram shows a series of peaks, each peak corre- sponding to one component of the mixture. The time required for a component to emerge from the column from the time of its injection into the column is known as the retention time, which is a useful identifying characteristic of a material. Figure 5–6(a) shows the chromatogram of two bar- biturates; each barbiturate has tentatively been identified by comparing its retention time to those of known barbiturates, shown in Figure 5–6(b). (See Appendix III for chromatographic condi- tions.) However, because other substances may have comparable retention times under similar chromatographic conditions, gas chromatography cannot be considered an absolute means of iden- tification. Conclusions derived from this technique must be confirmed by other testing procedures.

An added advantage of gas chromatography is that it is extremely sensitive and can yield quantitative results. The amount of substance passing through the GC detector is proportional to the peak area recorded; therefore, by chromatographing a known concentration of a material and comparing it to the unknown, the amount of the sample may be determined by proportion. Gas chromatography has sufficient sensitivity to detect and quantitate materials at the nanogram (0.000000001 gram or 1 � 10�9 gram) level.1

PYROLYSIS GC An important extension of the application of gas chromatography to forensic sci- ence is the technique of pyrolysis gas chromatography. Many solid materials commonly encountered as physical evidence—for example, paint chips, fibers, and plastics—cannot be readily dissolved in a solvent for injection into the gas chromatograph. Thus, under normal conditions these substances cannot be subjected to gas chromatographic analysis. However, materials such as these can be heated or pyrolyzed to high temperatures (500–1000°C) so that they will decompose into numerous gaseous products. Pyrolyzers permit these gaseous products to enter the carrier gas stream, where they flow into and through the GC column. The pyrolyzed material can then be characterized by the pattern pro- duced by its chromatogram or pyrogram. Figure 5–7 illustrates the pyrogram of a paint chip. The complexity of the paint pyrogram serves as a “fingerprint” of the material and gives the examiner many points to compare with other paints that are analyzed in a similar fashion.

1 Powers of 10 are quite useful and simple for handling large or small numbers. The exponent expresses the number of places the decimal point must be moved. If the exponent is positive, the decimal point is moved to the right; if it is negative, the decimal point is moved to the left. Thus, to express 1 � 10�9 as a number, the decimal point is simply moved nine places to the left of 1.

pyrolysis The decomposition of organic matter by heat

WEBEXTRA 5.1 Watch the Gas Chromatograph at Work http://www.mycrimekit.com

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ORGANIC ANALYSIS 127

High-Performance Liquid Chromatography (HPLC) Recall that a chromatographic system requires a moving phase and a stationary phase in contact with each other. The previous section described gas chromatography, in which the stationary phase is a thin film and the moving phase is a gas. However, by changing the nature of these phases, one can create different forms of chromatography. One form finding increasing utility in crime laboratories is high-performance liquid chromatography (HPLC). Its moving phase is a liquid that is pumped through a column filled with fine solid particles. In one form of HPLC, the

0 1 2 3 4 5 6 7 8 9 10 11 12

0 1 2 3 4 5 6 7 8 9 10 11 12

Pentobarbital

Secobarbital

TIME (MINUTES)(a)

Butabarbital

Amobarbital

Pentobarbital

Secobarbital

Phenobarbital

TIME (MINUTES)(b)

FIGURE 5–6 (a) An unknown mixture of barbiturates is identified by comparing its retention times to (b), a known mixture of barbiturates. Courtesy Varian Inc., Palo Alto, Calif.

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128 CHAPTER 5

surfaces of these solid particles are chemically treated and act as the stationary phase. As the liq- uid moving phase is pumped through the column, a sample is injected into the column. As the liquid carries the sample through the column, different components are retarded to different degrees, depending on their interaction with the stationary phase. This leads to a separation of the different components making up the sample mixture.

The major advantage of HPLC is that the entire process takes place at room temperature. With GC, the sample must first be vaporized and made to travel through a heated column. Hence, any materials sensitive to high temperatures may not survive their passage through the column. In such situations, the analyst may turn to HPLC as the method of choice. Organic explosives are gener- ally heat sensitive and therefore more readily separated by HPLC. Likewise, heat-sensitive drugs, such as LSD, lend themselves to analysis by HPLC.

Thin-Layer Chromatography (TLC) The technique of thin-layer chromatography (TLC) uses a solid stationary phase and a moving liquid phase to separate the constituents of a mixture.

THE TLC PROCESS A thin-layer plate is prepared by coating a glass plate with a thin film of a granular material, usually silica gel or aluminum oxide. This granular material serves as the solid stationary phase and is usually held in place on the plate with a binding agent such as plaster of Paris. If the sample to be analyzed is a solid, it must first be dissolved in a suitable solvent and a few microliters of the solution spotted with a capillary tube onto the granular surface near the lower edge of the plate. A liquid sample may be applied directly to the plate in the same manner. The plate is then placed upright into a closed chamber that contains a selected liquid, with care that the liquid does not touch the sample spot.

The liquid slowly rises up the plate by capillary action. This rising liquid is the moving phase in thin-layer chromatography. As the liquid moves past the sample spot, the components of the sample become distributed between the stationary solid phase and the moving liquid phase. The components with the greatest affinity for the moving phase travel up the plate faster than

0 TIME (MINUTES)

2 4 6 8 10 12 14

FIGURE 5–7 Pyrogram of a GM automobile paint. Courtesy Varian Inc., Palo Alto, Calif.

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ORGANIC ANALYSIS 129

those that have greater affinity for the stationary phase. When the liquid front has moved a sufficient distance (usually 10 cm), the development is complete, and the plate is removed from the chamber and dried (see Figure 5–8). An example of the chromatographic separation of ink is shown in Figure 5–9.

VISUALIZING SUBSTANCES Because most compounds are colorless, no separation will be noticed after development unless the materials are visualized. To accomplish this, the plates are placed under ultraviolet light, revealing select materials that fluoresce as bright spots on a dark background. When a fluorescent dye has been incorporated into the solid phase, nonfluorescent substances appear as dark spots against a fluorescent background when exposed to the ultravio- let light. In a second method of visualization, the plate is sprayed with a chemical reagent that reacts with the separated substances and causes them to form colored spots. Figure 5–10 shows the chromatogram of a marijuana extract that has been separated into its components by TLC and visualized by having been sprayed with a chemical reagent.

Sample spot

Very thin coating of silica gel or aluminum oxide

(a) (b)

Rising solvent; original spot has separated into several spots

FIGURE 5–8 (a) In thin-layer chromatography, a liquid sample is spotted onto the granular surface of a gel-coated plate. (b) The plate is placed into a closed chamber that contains a liquid. As the liquid rises up the plate, the components of the sample distribute themselves between the coating and the moving liquid. The mixture is separated, with substances with a greater affinity for the moving liquid traveling up the plate at a faster speed.

FIGURE 5–9 (a) The liquid phase begins to move up the stationary phase. (b) Liquid moves past the ink spot carrying the ink components up the stationary phase. (c) The moving liquid has separated the ink into its several components. Courtesy Richard Megna, Fundamental Photographs, NYC

fluoresce To emit visible light when exposed to light of a shorter wavelength— that is, ultraviolet light

(a) (b) (c)

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130 CHAPTER 5

IDENTIFYING SUBSTANCES Once the components of a sample have been separated, their iden- tification must follow. For this, the questioned sample must be developed alongside an authentic or standard sample on the same TLC plate. If both the standard and the unknown travel the same distance up the plate from their origins, they can tentatively be identified as being the same. For example, suppose a sample suspected of containing heroin and quinine is chromatographed alongside known heroin and quinine standards, as shown in Figure 5–11. The identity of the sus- pect material is confirmed by comparing the migration distances of the heroin and quinine stan- dards against those of the components of the unknown material. If the distances are the same, a tentative identification can be made. However, such an identification cannot be considered definitive because numerous other substances can migrate the same distance up the plate when chromatographed under similar conditions. Thus, thin-layer chromatography alone cannot pro- vide an absolute identification; it must be used in conjunction with other testing procedures to prove absolute identity.

The distance a spot has traveled up a thin-layer plate can be assigned a numerical value known as the Rf value. This value is defined as the distance traveled by the component divided by the distance traveled by the moving liquid phase. For example, in Figure 5–11 the moving phase traveled 10 centimeters up the plate before the plate was removed from the tank. After visualization, the heroin spot moved 8 centimeters, which has an Rf value of 0.8; the quinine migrated 4 centimeters, for an Rf value of 0.4.

FIGURE 5–10 Thin-layer chromatogram of a marijuana extract. Courtesy Sirchie Finger Print Laboratories, Youngsville, N.C., www.sirchie.com

FIGURE 5–11 Chromatograms of known heroin (1) and quinine (2) standards alongside suspect sample (3).

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Thousands of possible combinations of liquid and solid phases can be chosen in thin-layer chromatography. Fortunately, years of research have produced much published data relating to the proper selection of TLC conditions for separating and identifying specific classes of substances—for example, drugs, dyes, and petroleum products. These references, along with the experience of the analyst, will aid in the proper selection of TLC conditions for specific problems.

Thin-layer chromatography is a powerful tool for solving many of the analytical prob- lems presented to the forensic scientist. The method is both rapid and sensitive; moreover, less than 100 micrograms of suspect material are required for the analysis. In addition, the equipment necessary for TLC work has minimal cost and space requirements. Importantly, numerous samples can be analyzed simultaneously on one thin-layer plate. The principal application of this technique is in the detection and identification of components in complex mixtures.

Electrophoresis Electrophoresis is somewhat related to thin-layer chromatography in that it separates materials according to their migration rates on a stationary solid phase. However, it does not use a mov- ing liquid phase to move the material; instead, an electrical potential is placed across the sta- tionary medium. The nature of this medium can vary; most forensic applications call for a starch or agar gel coated onto a glass plate. Under these conditions, only substances that possess an electrical charge migrate across the stationary phase (see Figure 5–12). The technique is partic- ularly useful for separating and identifying complex biochemical mixtures. In forensic science, electrophoresis finds its most successful application in the characterization of DNA in dried blood (see Figure 5–13).

Because many substances in blood carry an electrical charge, they can be separated and identified by electrophoresis. As shown in Figure 5–12, mixtures of DNA fragments can be sep- arated by gel electrophoresis by taking advantage of the fact that the rate of movement of DNA across a gel-coated plate depends on the molecule’s size. Smaller DNA fragments move at a faster rate along the plate than larger DNA fragments. This technique will be discussed in further detail in Chapters 10 and 11.

electrophoresis A technique for separating molecules through migration on a support medium while under the influence of an electrical potential

Power source Mixtures of DNA fragments of different sizes placed on gel-coated plate

Gel-coated plate

(a)

Power source

Electric potential applied to plate

Substances with an electrical charge migrate across plate

(b)

Power source

Completed gel

Longer fragments move more slowly

Shorter fragments move more quickly

Separated bands allow analyst to characterize DNA in dried blood

(c)

FIGURE 5–12

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visible light Colored light ranging from red to violet in the electromagnetic spectrum

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132 CHAPTER 5

Spectrophotometry We have already seen that when white light passes through a glass prism, it is dispersed into a continuous spectrum of colors. This phenomenon demonstrates that white light is not homoge- neous but is actually composed of a range of colors that extends from red through violet. Simi- larly, the observation that a substance has a color is also consistent with this description of white light. For example, when light passes through a red glass, the glass absorbs all the component col- ors of light except red, which passes through or is transmitted by the glass. Likewise, one can de- termine the color of an opaque object by observing its ability to absorb some of the component colors of light while reflecting others back to the eye. Color is thus a visual indication that ob- jects absorb certain portions of visible light and transmit or reflect others. Scientists have long recognized this phenomenon and have learned to characterize different chemical substances by the type and quantity of light they absorb.

Theory of Light To understand why materials absorb light, one must first comprehend the nature of light. Two simple models explain light’s behavior. The first model describes light as a continuous wave; the second depicts it as a stream of discrete energy particles. Together, these two very different de- scriptions explain all of the observed properties of light, but by itself, no one model can explain all the facets of the behavior of light.

LIGHT AS A WAVE The wave concept depicts light as having an up-and-down motion of a con- tinuous wave, as shown in Figure 5–14. Several terms are used to describe such a wave. The dis- tance between two consecutive crests (or one trough to the next trough) is called the wavelength; the Greek letter lambda (�) is used as its symbol, and the unit of nanometers is frequently used to express its value. The number of crests (or troughs) passing any one given point in a unit of time is defined as the frequency of the wave. Frequency is normally designated by the letter f and is expressed in cycles per second (cps). The speed of light in a vacuum is a universal constant at 300 million meters per second and is designated by the symbol c. Frequency and wavelength are inversely proportional to one another, as shown by the relationship expressed in Equation (5–1):

F � c/� (5–1)

THE ELECTROMAGNETIC SPECTRUM Actually, visible light is only a small part of a large fam- ily of radiation waves known as the electromagnetic spectrum. All electromagnetic waves travel at the speed of light (c) and are distinguishable from one another only by their different wavelengths or frequencies. (Figure 5–15 illustrates the various types of electromagnetic waves in order of decreasing frequency.) Hence, the only property that distinguishes X-rays from radio waves is the different frequencies the two types of waves possess. Similarly, the range of colors that make up the visible spectrum can be correlated with frequency. For instance, the lowest frequencies of visi-

FIGURE 5–13 DNA fragments separated by gel electrophoresis are visualized under a UV light. Courtesy Cytographics, Visuals Unlimited

frequency The number of waves that pass a given point per second

wavelength The distance between crests of adjacent waves

electromagnetic spectrum The entire range of radiation energy from the most energetic cosmic rays to the least energetic radio waves

X-ray A high-energy, short-wavelength form of electromagnetic radiation

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ORGANIC ANALYSIS 133

ble light are red; waves with a lower frequency fall into the invisible infrared (IR) region. The high- est frequencies of visible light are violet; waves with a higher frequency extend into the invisible ul- traviolet (UV) region. No definite boundaries exist between any colors or regions of the electromagnetic spectrum; instead, each region is composed of a continuous range of frequencies, each blending into the other.

Ordinarily, light in any region of the electromagnetic spectrum is a collection of waves pos- sessing a range of wavelengths. Under normal circumstances, this light comprises waves that are all out of step with each other (incoherent light). However, scientists can now produce a beam of light that has all of its waves pulsating in unison (see Figure 5–16). This is called coherent light or a laser (light amplification by the stimulated emission of radiation) beam. Light in this form is very intense and can be focused on a very small area. Laser beams can be focused to pinpoints that are so intense that they can zap microscopic holes in a diamond.

LIGHT AS A PARTICLE As long as electromagnetic radiation is moving through space, its be- havior can be described as that of a continuous wave; however, once radiation is absorbed by a substance, the model of light as a stream of discrete particles must be invoked to best describe its behavior. Here, light is depicted as consisting of energy particles that are known as photons. Each

λ

λ

FIGURE 5–14 The frequency of the lower wave is twice that of the upper wave.

Visible light

Gamma rays

High frequency Low frequency

Short wavelength Energy increases

Long wavelength

X rays Ultraviolet Infrared Microwaves Radio waves

FIGURE 5–15 The electromagnetic spectrum.

laser An acronym for light amplification by stimulated emission of radiation; light that has all its waves pulsating in unison

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134 CHAPTER 5

photon has a definite amount of energy associated with its behavior. This energy is related to the frequency of light, as shown by Equation (5–2):

E � hf (5–2)

where E specifies the energy of the photon, f is the frequency of radiation, and h is a univer- sal constant called Planck’s constant. As shown by Equation (5–2), the energy of a photon is directly proportional to its frequency. Therefore, the photons of ultraviolet light will be more energetic than the photons of visible or infrared light, and exposure to the more energetic photons of X-rays presents more danger to human health than exposure to the photons of radio waves.

Absorption of Electromagnetic Radiation Just as a substance can absorb visible light to produce color, many of the invisible radiations of the electromagnetic spectrum are likewise absorbed. This absorption phenomenon is the basis for spectrophotometry, an important analytical technique in chemical identification. Spec- trophotometry measures the quantity of radiation that a particular material absorbs as a function of wavelength or frequency.

We have already observed in the description of color that an object does not absorb all the visible light it is exposed to; instead, it selectively absorbs some frequencies and reflects or trans- mits others. Similarly, the absorption of other types of electromagnetic radiation by chemical sub- stances is also selective. These key questions must be asked: Why does a particular substance absorb only at certain frequencies and not at others? And are these frequencies predictable? The answers are not simple. Scientists find it difficult to predict with certainty all the frequencies at which any one substance will absorb in a particular region of the electromagnetic spectrum. What is known, however, is that a chemical substance absorbs photons of radiation with a frequency that corresponds to an energy requirement of the substance, as defined by Equation (5–2). Different materials have different energy requirements and therefore absorb at different frequencies. Most important to the analyst is that these absorbed frequencies are measurable and can be used to char- acterize a material.

The selective absorption of a substance is measured by an instrument called a spectrophotometer, which produces a graph or absorption spectrum that depicts the absorption of light as a function of wavelength or frequency. The absorption of UV, visible, and IR radiation is

Coherent radiation

Incoherent radiation

FIGURE 5–16 Coherent and incoherent radiation.

photon A small packet of electromagnetic radiation energy; each photon contains a unit of energy equal to the product of Planck’s constant and the frequency of radiation: E � hf

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ORGANIC ANALYSIS 135

particularly applicable for obtaining qualitative data pertaining to the identification of organic substances.

Absorption at a single wavelength or frequency of light is not 100 percent complete— some radiation is transmitted or reflected by the material. Just how much radiation a sub- stance absorbs is defined by a fundamental relationship known as Beer’s law, shown in Equation (5–3):

A � kc (5–3)

Here, A symbolizes the absorption or the quantity of light taken up at a single frequency, c is the concentration of the absorbing material, and k is a proportionality constant. This relationship shows that the quantity of light absorbed at any frequency is directly proportional to the concen- tration of the absorbing species; the more material you have, the more radiation it will absorb. By defining the relationship between absorbance and concentration, Beer’s law permits spectropho- tometry to be used as a technique for quantification.

The Spectrophotometer The spectrophotometer measures and records the absorption spectrum of a chemical substance. The basic components of a simple spectrophotometer are the same regardless of whether it is designed to measure the absorption of UV, visible, or IR radiation. These components are illus- trated in Figure 5–17. They include (1) a radiation source, (2) a monochromator or frequency selector, (3) a sample holder, (4) a detector to convert electromagnetic radiation into an electrical signal, and (5) a recorder to produce a record of the signal.

The choice of source will vary with the type of radiation desired. For visible radiation, an ordinary tungsten bulb provides a convenient source of radiation. In the UV region, a hydrogen or deuterium discharge lamp is normally used, and a heated molded rod containing a mixture of rare-earth oxides is a good source of IR light.

The function of the monochromator is to select a single wavelength or frequency of light from the source—monochromatic light. Some inexpensive spectrophotometers pass the light through colored glass filters to remove all radiation from the beam except for a desired range of wavelengths. More precise spectrophotometers use a prism or diffraction grating to disperse radiation into its component wavelengths or frequencies.2 The desired wavelength is obtained when the dispersed radiation is focused onto a narrow slit that permits only selected wavelengths to pass through.

Most laboratory infrared spectrophotometers use Fourier transform analysis to measure the wavelengths of light at which a material will absorb in the infrared spectrum. This approach does not use any dispersive elements that select single wavelengths or frequencies of light emitted from a source; instead, the heart of a Fourier transform infrared (FT-IR) spectrometer is the Michelson interferometer. The interferometer uses a beam-splitting prism and two mirrors, one movable and one stationary, to direct light toward a sample. As the wavelengths pass through the sample and reach a detector, they are all measured simultaneously. A mathematical opera- tion, the Fourier transform method, is used to decode the measured signals and record the wavelength data. These Fourier calculations are rapidly carried out by a computer. In a matter of seconds, a computer-operated FT-IR instrument can produce an infrared absorption pattern compatible to one generated by a prism instrument.

Sample preparation varies with the type of radiation being studied. Absorption spectra in the UV and visible regions are usually obtained from samples that have been dissolved in an appro- priate solvent. Because the cells holding the solution must be transparent to the light being measured, glass cells are used in the visible region and quartz cells in the ultraviolet region. Prac- tically all substances absorb in some region of the IR spectrum, so sampling techniques must be modified to measure absorption in this spectral region; special cells made out of sodium chloride or potassium bromide are commonly used because they will not absorb light over a wide range of the IR portion of the electromagnetic spectrum.

monochromatic light Light having a single wavelength or frequency

monochromator A device for isolating individual wavelengths or frequencies of light

2A diffraction grating is made by scratching thousands of parallel lines on a transparent surface such as glass. As light passes through the narrow spacings between the lines, it spreads out and produces a spectrum similar to that formed by a prism.IS

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Detector RecorderRadiation source(a) Monochromator

Prism disperses radiation into component wavelengths

Prism

Sample cell

Slit

FIGURE 5–17 Parts of a simple spectrophotometer.

DetectorRadiation source(b) Monochromator

Prism

Sample cell

Slit

Recorder

Slit allows only selected wavelengths or frequencies of radiation to pass through

DetectorRadiation source(c) Monochromator Sample cell Recorder

Prism Slit

Radiation passes through sample, which absorbs certain frequencies

Detector measures absorption of radiation by the sample and converts the radiation into an electrical signal

Radiation source

(d)

Monochromator Sample cell

Recorder

Prism Slit

DetectorRadiation source

(e)

Monochromator

Prism

Sample cell

Slit

Recorder

Recorder translates electrical signal into recording of the absorption spectrum

The absorption spectrum of a chemical substance allows spectrophotometry to be used for identification.

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ORGANIC ANALYSIS 137

The detector measures the quantity of radiation that passes through the sample by converting it to an electrical signal. UV and visible spectrophotometers employ photoelectric tube detectors. A signal is generated when the photons strike the tube surface to produce a current that is directly proportional to the intensity of the light transmitted through the sample. When this signal is com- pared to the intensity of light that is transmitted to the detector in the absence of an absorbing ma- terial, the absorbance of a substance can be determined at each wavelength or frequency of light selected. The signal from the detection system is then fed into a recorder, which plots absorbance as a function of wavelength or frequency. Modern spectrophotometers are designed to trace an entire absorption spectrum automatically.

Ultraviolet, Visible, and Infrared Spectrophotometry Ultraviolet and visible spectrophotometry measure the absorbance of UV and visible light as a function of wavelength or frequency. For example, the UV absorption spectrum of heroin shows a maximum absorption band at a wavelength of 278 nanometers (see Figure 5–18). This shows that the simplicity of a UV spectrum facilitates its use as a tool for determining a ma- terial’s probable identity. For instance, a white powder may have a UV spectrum comparable to heroin and therefore may be tentatively identified as such. (Fortunately, sugar and starch, common diluents of heroin, do not absorb UV light.) However, this technique will not provide a definitive result; other drugs or materials may have a UV absorption spectrum similar to that of heroin. But this lack of specificity does not diminish the value of the technique because the analyst has quickly eliminated thousands of other possible drugs from consideration and can now proceed to conduct other confirmatory tests, such as thin-layer or gas chromatography, to complete the identification.

In contrast to the simplicity of a UV spectrum, absorption in the infrared region provides a far more complex pattern. Figure 5–19 depicts the IR spectra of heroin and secobarbital. Here, the absorption bands are so numerous that each spectrum can provide enough characteristics to identify a substance specifically. Different materials always have distinctively different in- frared spectra; each IR spectrum is therefore equivalent to a “fingerprint” of that substance and no other. This technique is one of the few tests available to the forensic scientist that can be considered specific in itself for identification. The IR spectra of thousands of organic compounds have been collected, indexed, and cataloged to serve as invaluable references for identifying organic substances.

infrared Invisible short frequencies of light before red in the visible spectrum

ultraviolet Invisible long frequencies of light beyond violet in the visible spectrum

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Heroin

Ab so

rb an

ce

250 300 350 Wavelength in nanometers

FIGURE 5–18 The ultraviolet spectrum of heroin.

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138 CHAPTER 5

Mass Spectrometry Aprevious section discussed the operation of the gas chromatograph. This instrument is one of the most important tools in a crime laboratory. Its ability to separate the components of a complex mixture is unsurpassed. However, gas chromatography (GC) does have one important drawback—its inability to produce specific identification. A forensic chemist cannot unequivocally state the identification of a substance based solely on a retention time as determined by the gas chromatograph. Fortunately, coupling the gas chromatograph to a mass spectrometer has largely overcome this problem.

The separation of a mixture’s components is first accomplished on the gas chromatograph. A di- rect connection between the GC column and the mass spectrometer then allows each component to flow into the spectrometer as it emerges from the gas chromatograph. In the mass spectrometer, the material enters a high-vacuum chamber where a beam of high-energy electrons is aimed at the sample

0.00

100.00 %T

4000 3500 3000 2500 2000 1500 1000 500 Wavenumber cm–1

FIGURE 5–19 (a) Infrared spectrum of heroin. (b) Infrared spectrum of secobarbital.

0.00

100.00 %T

4000 3500 3000 2500 2000 1500 1000 500 Wavenumber cm–1

(a)

(b)

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ORGANIC ANALYSIS 139

molecules. The electrons collide with the molecules, causing them to lose electrons and to acquire a positive charge (commonly called ions). These positively charged molecules or ions are unstable or are formed with excess energy and almost instantaneously decompose into numerous smaller frag- ments. The fragments then pass through an electric or magnetic field, where they are separated ac- cording to their masses. The unique feature of mass spectrometry is that under carefully controlled conditions, no two substances produce the same fragmentation pattern. In essence, one can think of this pattern as a “fingerprint” of the substance being examined (see Figure 5–20).

The technique thus provides a specific means for identifying a chemical structure. It is also sensitive to minute concentrations. At present, mass spectrometry finds its widest application in the identification of drugs; however, further research is expected to yield significant applications for identifying other types of physical evidence. Figure 5–21 illustrates the mass spectra of heroin

ion An atom or molecule bearing a positive or negative charge

D

C

B

A

A B

C

D

Chromatogram Spectra

Separation Identification

GC MS

FIGURE 5–20 How GC/MS works. Left to right, the sample is separated into its components by the gas chromatograph, and then the components are ionized and identified by characteristic fragmentation patterns of the spectra produced by the mass spectrometer. Courtesy Agilent Technologies, Inc., Palo Alto, Calif.

43

94 146

204 215

268

327

369

100 200 300 Mass/charge

(a)

Ab un

da nc

e

42

122 150

182

272

82

303

100 150 300 Mass/charge

(b)

Ab un

da nc

e

25020050

FIGURE 5–21 (a) Mass spectrum of heroin. (b) Mass spectrum of cocaine.

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140 CHAPTER 5

and cocaine; each line represents a fragment of a different mass (actually the ratio of mass to charge), and the line height reflects the relative abundance of each fragment. Note how different the fragmentation patterns of heroin and cocaine are. Each mass spectrum is unique to each drug and therefore serves as a specific test for identifying it.

The combination of the gas chromatograph and mass spectrometer is further enhanced when a computer is added to the system. The integrated gas chromatograph/mass spectrometer/computer system provides the ultimate in speed, accuracy, and sensitivity. With the ability to record and store in its memory several hundred mass spectra, such a system can detect and identify substances pres- ent in only one-millionth-of-a-gram quantities. Furthermore, the computer can be programmed to compare an unknown spectrum against a comprehensive library of mass spectra stored in its mem- ory. The advent of personal computers and microcircuitry has made it possible to design mass spec- trometer systems that can fit on a small table. Such a unit is pictured in Figure 5–22. Research-grade mass spectrometers are found in laboratories as larger floor-model units (see Figure 5–23).

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1. Injection port 3. Ion source

4. Quadrupole 6. Data system

5. Detector2. GC column

FIGURE 5–22 A tabletop mass spectrometer. (1) The sample is injected into a heated inlet port, and a carrier gas sweeps it into the column. (2) The GC column separates the mixture into its components. (3) In the ion source, a filament wire emits electrons that strike the sample molecules, causing them to fragment as they leave the GC column. (4) The quadrupole, consisting of four rods, separates the fragments according to their mass. (5) The detector counts the fragments passing through the quadrupole. The signal is small and must be amplified. (6) The data system is responsible for total control of the entire GC/MS system. It detects and measures the abundance of each fragment and displays the mass spectrum. Courtesy Agilent Technologies, Inc., Palo Alto, Calif.

FIGURE 5–23 A scientist injecting a sample into a research- grade mass spectrometer. Courtesy Geoff Tompkinson/Science Photo Library, Photo Researchers, Inc.

Virtual Forensics Lab

Thin-Layer Chromatography of Ink To perform a virtual thin-layer chromatography lab, go to www. pearsoncustom.com/us/vlm/

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The proper selection of analytical techniques that will allow the forensic scientist to identify or compare matter can best be un- derstood by categorizing all substances into one of two broad groups: organics and inorganics. In general, organic substances contain carbon. Inorganic materials encompass all other known chemical substances. Another consideration in selecting an an- alytical technique is the need for either a qualitative or a quan- titative determination. The former relates just to the identity of the material, whereas the latter requires the determination of the percentage composition of the components of a mixture.

Chromatography, spectrophotometry, and mass spectrome- try are all readily used by a forensic scientist to identify or compare organic materials. Chromatography is a means of sep- arating and tentatively identifying the components of a mixture. Spectrophotometry is the study of the absorption of light by chemical substances. Mass spectrometry characterizes organic molecules by observing their fragmentation pattern after their collision with a beam of high-energy electrons. Gas chromatog- raphy (GC) separates mixtures on the basis of their distribution between a stationary liquid phase and a mobile gas phase. In GC, the moving phase is actually a gas called the carrier gas, which flows through a column. The stationary phase is a thin film of liquid contained within the column. After a mixture has tra- versed the length of the column, it emerges separated into its

components. The written record of this separation is called a chromatogram.Adirect connection between the GC column and the mass spectrometer allows each component to flow into the mass spectrometer as it emerges from the GC. Fragmentation of each component by high-energy electrons produces a “finger- print” pattern of the substance being examined.

Other forms of chromatography applicable to forensic science are high-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC). HPLC separates com- pounds using a stationary phase and a mobile liquid phase and is used with temperature-sensitive compounds. TLC uses a solid stationary phase, usually coated onto a glass plate, and a mobile liquid phase to separate the components of the mixture. A technique analogous to TLC is electrophoresis, in which ma- terials are forced to move across a gel-coated plate under the in- fluence of an electrical potential. In this manner, substances such as proteins and DNA can be separated and characterized.

Most forensic laboratories use ultraviolet (UV) and in- frared (IR) spectrophotometers to characterize chemical com- pounds. In contrast to the simplicity of a UV spectrum, absorption in the infrared region provides a far more complex pattern. Different materials always have distinctively different infrared spectra; each IR spectrum is therefore equivalent to a “fingerprint” of that substance.

chapter summary

review questions

1. Anything that has mass and occupies space is defined as ___________.

2. The basic building blocks of all substances are the ___________.

3. The number of elements known today is ___________.

4. An arrangement of elements by similar chemical prop- erties is accomplished in the ___________ table.

5. A(n) ___________ is the smallest particle of an element that can exist.

6. Substances composed of two or more elements are called ___________.

7. A(n) ___________ is the smallest unit of a compound formed by the union of two or more atoms.

8. The physical state that retains a definite shape and vol- ume is a(n) ___________.

9. A gas (has, has no) definite shape or volume.

10. During the process of ___________, solids go directly to the gaseous state, bypassing the liquid state.

11. The attraction forces between the molecules of a liquid are (greater, less) than those in a solid.

12. Different ___________ are separated by definite visible boundaries.

13. Carbon-containing substances are classified as ___________.

14. ___________ substances encompass all non-carbon- containing materials.

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142 CHAPTER 5

15. A(n) ___________ analysis describes the identity of a material, and a(n) ___________ analysis relates to a determination of the quantity of a substance.

16. The study of the absorption of light by chemical substances is known as ___________.

17. A mixture’s components can be separated by the tech- nique of ___________.

18. True or False: Henry’s law describes the distribution of a volatile chemical compound between its liquid and gas phases. ___________

19. The (higher, lower) the solubility of a gas in a liquid, the greater its tendency to remain dissolved in that liquid.

20. True or False: In order for chromatography to occur, one phase must move continuously in one direction over a sta- tionary phase. ___________

21. A technique that separates mixtures on the basis of their distribution between a stationary liquid phase and a moving gas phase is ___________.

22. The time required for a substance to travel through the gas chromatographic column is a useful identifying characteristic known as ___________.

23. Solid materials that are not readily dissolved in solvents for injection into the gas chromatograph can be ___________ into numerous gaseous products before entering the gas chromatograph.

24. A major advantage of high-performance liquid chro- matography is that the entire process takes place at ___________ temperature.

25. A technique that uses a moving liquid phase and a sta- tionary solid phase to separate mixtures is ___________.

26. Because most chemical compounds are colorless, the fi- nal step of the thin-layer development usually requires that they be ___________ by spraying with a chemical reagent.

27. The distance a spot has traveled up a thin-layer plate can be assigned a numerical value known as the ___________ value.

28. True or False: Thin-layer chromatography yields the positive identification of a material. ___________

29. The migration of materials along a stationary phase un- der the influence of an electrical potential describes the technique of ___________.

30. True or False: Color is a usual indication that substances selectively absorb light. ___________

31. The distance between two successive identical points on a wave is known as ___________.

32. True or False: Frequency and wavelength are directly proportional to one another. ___________

33. Light, X-rays, and radio waves are all members of the ___________ spectrum.

34. Red light is (higher, lower) in frequency than violet light.

35. A beam of light that has all of its waves pulsating in uni- son is called a(n) ___________.

36. One model of light depicts it as consisting of energy par- ticles known as ___________.

37. True or False: The energy of a light particle (photon) is directly proportional to its frequency. ___________

38. Red light is (more, less) energetic than violet light.

39. The selective absorption of electromagnetic radiation by materials (can, cannot) be used as an aid for identifi- cation.

40. The amount of radiation a substance will absorb is di- rectly proportional to its concentration as defined by ___________ law.

41. The ___________ is the instrument used to measure and record the absorption spectrum of a chemical substance.

42. The function of the ___________ is to select a single frequency of light emanating from the spectrophotome- ter’s source.

43. An (ultraviolet, infrared) absorption spectrum provides a unique “fingerprint” of a chemical substance.

44. The technique of ___________ exposes molecules to a beam of high-energy electrons in order to fragment them.

45. True or False: A mass spectrum is normally considered a specific means for identifying a chemical substance. ___________

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ORGANIC ANALYSIS 143

application and critical thinking

1. Forensic drug analyst Rose Thomas receives a potential drug sample for analysis. The appearance of the powder suggests that it is adulterated and may contain more than one substance. Would spectrometry be a good analytical tool in this case? If not, what other technique could be used?

2. Because of a budget cut at the crime lab, Rose Thomas must use an analytical technique that will be relatively cheap and accommodate many samples at one time. Which chromatographic method would be best in this case? Why?

3. The figure below shows a chromatogram of a known mixture of barbiturates. Based on this figure, answer the following questions:

a. What barbiturate detected by the chromatogram had the longest retention time?

b. Which barbiturate had the shortest retention time?

c. What is the approximate retention time of amobarbital?

further references

Northrop, David, “Forensic Applications of High-Performance Liquid Chromatography and Capillary Electrophoresis,” in R. Saferstein, ed., Forensic Science Handbook, vol. 1, 2nd ed. Upper Saddle River, N.J.: Prentice Hall, 2002.

Saferstein, Richard, “Forensic Applications of Mass Spec- trometry,” in R. Saferstein, ed., Forensic Science Hand- book, vol. 1, 2nd ed. Upper Saddle River, N.J.: Prentice Hall, 2002.

Stafford, David T., “Forensic Capillary Gas Chromatogra- phy,” in R. Saferstein, ed., Forensic Science Handbook, vol. 2, 2nd ed. Upper Saddle River, N.J.: Prentice Hall, 2005.

Suzuki, Edward M., “Forensic Applications of Infrared Spec- troscopy,” in R. Saferstein, ed., Forensic Science Hand- book, Vol. 3, 2nd ed. Upper Saddle River, N.J.: Prentice Hall, 2010.

0 1 2 3 4 5 6 7 8 9 10 11 12

Butabarbital

Amobarbital

Pentobarbital

Secobarbital

Phenobarbital

TIME (MINUTES)(b)

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What Killed Napoleon?

Napoleon I, emperor of France, was sent into exile on the remote island of St. Helena by the British after his defeat at the Battle of Waterloo in 1815. St. Helena was hot, unsanitary, and rampant with disease. There, Napoleon was confined to a large reconstructed agricultural building known as Longwood House. Boredom and unhealthy living conditions gradually took their toll on Napoleon’s mental and physical state. He began suffering from severe abdominal pains and experienced swelling of the ankles and general weakness of his limbs. From the fall of 1820, Napoleon’s health began to deteriorate rapidly until death arrived on May 5, 1821. An autopsy concluded the cause of death to be stomach cancer.

It was inevitable that dying under British control, as Napoleon did, would bring with it numerous conspiratorial theories to account for his death. One of the more fascinating inquiries was conducted by a Swedish dentist, Sven Forshufvud, who systematically correlated the clinical symptoms of Napoleon’s last days to those of arsenic poisoning. For Forshufvud, the key to unlocking the cause of Napoleon’s death rested with Napoleon’s hair. Forshufvud arranged to have Napoleon’s hair measured for arsenic content by neutron activation analysis and

found it consistent with arsenic poisoning over a lengthy period of time. Nevertheless, the cause of Napoleon’s demise is still a

matter for debate and speculation. Other Napoleon hairs collected in 1805 and 1814 have also shown high concentrations of arsenic, giving rise to the speculation that Napoleon was

innocently exposed to arsenic. Even hair collected from Napoleon’s three sisters, son, and first wife show significant levels of arsenic. Some question whether Napoleon even had clinical symptoms associated with arsenic poisoning. In truth, forensic science may never be able to answer the question “What killed Napoleon?”

headline news

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After studying this chapter you should be able to: • Describe the usefulness of trace elements for forensic

comparison of various types of physical evidence

• Distinguish continuous and line emission spectra

• Understand the parts of a simple emission spectrograph

• List the parts of a simple atomic absorption spectrophotometer

• Define and distinguish protons, neutrons, and electrons

• Define and distinguish atomic number and atomic mass number

• Appreciate the phenomenon of how an atom absorbs and releases energy in the form of light

• Explain the concept of an isotope

• Understand how elements can be made radioactive

• Describe why an X-ray diffraction pattern is useful for chemical identification

inorganic analysis

alpha particle atomic mass atomic number beta particle continuous spectrum electron electron orbital emission spectrum excited state gamma ray isotope line spectrum neutron nucleus proton radioactivity X-ray diffraction

KEY TERMS

chapter 6 Le

ar ni

ng O

b je

ct iv

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146 CHAPTER 6

TABLE 6–1 Elemental Abundances as Percentages in the Earth’s Crust

Element Percentage by Weight

Oxygen 47.3 Silicon 27.7 Aluminum 7.9 Iron 4.5 Calcium 3.5 Sodium 2.5 Potassium 2.5 Magnesium 2.2 Titanium 0.5 Hydrogen 0.2 Other elements 1.2

Inorganics as Forensic Evidence In the previous chapter, analytical techniques were described for characterizing a class of matter known as organics. Generally, these materials contain carbon. Although organic substances con- stitute a substantial portion of the physical evidence submitted to crime laboratories, carbon does not appear among the earth’s most abundant elements. Surprisingly, about three-quarters of the weight of the earth’s crust is composed of only two elements—oxygen and silicon. In fact, only ten elements make up approximately 99 percent of the earth’s crust (see Table 6–1). The remain- ing elements may almost be considered impurities, although exceedingly important ones. Carbon, the element that is a constituent of most chemical compounds, constitutes less than 0.1 percent of the earth’s crust.

Considering these facts, it is certainly reasonable that non-carbon-containing substances—that is, inorganics—are encountered as physical evidence at crime scenes. One only has to consider the prevalence of metallic materials, such as iron, steel, copper, and aluminum, in our society to understand the possibilities of finding tools, coins, weapons, and metal scrapings at crime scenes.

Less well known, but perhaps almost as significant to the criminalist, is the use of inorganic chemicals as pigments in paints and dyes, the incorporation of inorganics into explosive formu- lations, and the prevalence of inorganic poisons such as mercury, lead, and arsenic.

To appreciate fully the role of inorganic analysis in forensic science, we must first examine its application to the basic objectives of the crime laboratory—identification and comparison of physical evidence. Identification of inorganic evidence is exemplified by a typical request to ex- amine an explosive formulation suspected of containing potassium chlorate, or perhaps to exam- ine a poisonous powder thought to be arsenic. In each case, the forensic scientist must perform tests that will ultimately determine the specific chemical identity of the suspect materials to the ex- clusion of all others. Only after completing the tests and finding their results identical to previously recorded tests for a known potassium chlorate or a known arsenic can the forensic scientist draw a valid conclusion about the chemical identity of the evidence.

However, comparing two or more objects in order to ascertain their common origin presents a different problem. For example, a criminalist may be asked to determine whether a piece of brass pipe found in the possession of a suspect compares to a broken pipe found at the crime scene. The condition of the two pipes may not allow for comparison by physically fitting together any bro- ken edges. Under these circumstances, the only alternative will be to attempt a comparison through chemical analysis. It is not enough for the analyst to conclude that the pipes are alike because they are brass (an alloy of copper and zinc). After all, hundreds of thousands of brass pipes exist, a situation that is hardly conducive to proving that these two particular pipes were at one time a single unit. The examiner must go a step further to try to distinguish these pipes from all others. Although this may not be possible, a comparison of the pipes’ trace elements—that is, elements present in small quantities—will provide a meaningful criterion for at least increasing the probability that the two pipes originated from the same source.

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INORGANIC ANALYSIS 147

TABLE 6–2 Elemental Analysis of Brass Alloys

Element High-Tensile Brass

(percentage) Manganese Brass

(percentage)

Copper 57.0 58.6 Aluminum 2.8 1.7 Zinc 35.0 33.8 Manganese 2.13 1.06 Iron 1.32 0.90 Nickel 0.48 1.02 Tin 0.64 1.70 Lead 0.17 0.72 Silicon 0.08 Nil

Source: R. L. Williams, “An Evaluation of the SEM with X-Ray Microanalyzer Accessory for Forensic Work,” in O. Johari and I. Corvin, eds., Scanning Electron Microscopy/1971 (Chicago: IIT Research Institute, 1971), p. 541.

Trace Elements Considering that most of our raw materials originate from the earth’s crust, it is not surprising that they are rarely obtained in pure form; instead, they include numerous elemental impurities that usually have to be eliminated through industrial processing. However, in most cases it is not economically feasible to completely exclude all such minor impurities, especially when their presence will have no effect on the appearance or performance of the final product. For this rea- son, many manufactured products, and even most natural materials, contain small quantities of elements present in concentrations of less than 1 percent.

For the criminalist, the presence of trace elements is particularly useful because they provide “in- visible” markers that may establish the source of a material or at least provide additional points for comparison. Table 6–2 illustrates how two types of brass alloys can readily be distinguished by their elemental composition. Similarly, the comparison of trace elements present in paint or other types of metallic specimens may provide particularly meaningful data with respect to source or origin. Foren- sic investigators have examined the evidential value of trace elements present in soil, fibers, and glass, as well as in all types of metallic objects. One example of this application occurred with the exami- nation of the bullet and bullet fragments recovered after the assassination of President Kennedy.

Evidence in the Assassination of President Kennedy Ever since President Kennedy was killed in 1963, questions have lingered about whether Lee Harvey Oswald was part of a conspiracy to assassinate the president or, as the Warren Commis- sion concluded, a lone assassin. In arriving at its conclusions, the Warren Commission recon- structed the crime as follows: Oswald fired three shots from behind the president while positioned in the Texas School Book Depository building. The president was struck by two bullets, with one bullet totally missing the president’s limousine. One bullet hit the president in the back, exited his throat, and then went on to strike Governor Connally, who was sitting in a jump seat in front of the president. The bullet hit Connally first in his back, then exited his chest, struck his right wrist, and temporarily lodged in his left thigh. This bullet was later found on the governor’s stretcher at the hospital. A second bullet in the skull fatally wounded the president.

In a room at the Texas School Book Depository, a 6.5-mm Mannlicher-Carcano military rifle was found with Oswald’s palm print on it. Also found were three spent 6.5-mm Western Cartridge Co./ Mannlicher-Carcano (WCC/MC) cartridge cases. Oswald, an employee of the depository, had been seen there that morning and also a few minutes after the assassination, disappearing soon there- after. He was apprehended a few miles from the depository nearly two hours after the shooting.

Critics of the Warren Commission have long argued that evidence exists that would prove Oswald did not act alone. Eyewitness accounts and acoustical data interpreted by some experts

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148 CHAPTER 6

President John F. Kennedy, Governor John Connally of Texas, and Mrs. Jacqueline Kennedy ride through Dallas moments before the assassination. Courtesy CORBIS-NY

have been used to advocate the contention that someone else fired at the president from a region in front of the limousine (the so-called grassy knoll). Furthermore, it is argued that the Warren Commission’s reconstruction of the crime relied on the assumption that only one bullet caused both the president’s throat wound and Connally’s back wound. Critics contend that such damage would have deformed and mutilated a bullet. Instead, the recovered bullet showed some flatten- ing, no deformity, and only about 1 percent weight loss.

In 1977, at the request of the U.S. House of Representatives Select Committee on Assassi- nations, the bullet taken from Connally’s stretcher along with bullet fragments recovered from the car and various wound areas were examined for trace element levels.

Lead alloys used for the manufacture of bullets contain an assortment of trace elements. For example, antimony is often added to lead as a hardening agent; copper, bismuth, and silver are other trace elements commonly found in bullet lead. In this case, the bullet and bullet frag- ments were compared for their antimony and silver content. Previous studies had amply demonstrated that the levels of these two elements are particularly important for characterizing WCC/MC bullets. Bullet lead from this type of ammunition ranges in antimony concentration from 20 to 1,200 parts per million (ppm) and 5 to 15 ppm in silver content.

As can be seen in Table 6–3, the samples designated Q1 and Q9 (the Connally stretcher bul- let and fragments from Connally’s wrist, respectively) are indistinguishable from one another in antimony and silver content. The samples Q2; Q4, 5; and Q14 (Q4, 5 being fragments from Kennedy’s brain, and Q2 and Q14 being fragments recovered from two different areas in the car) also are indistinguishable in antimony and silver content but are different from Q1 and Q9.

The conclusions derived from studying these results are as follows:

1. There is evidence of only two bullets—one composed of 815 ppm antimony and 9.3 ppm sil- ver, the other composed of 622 ppm antimony and 8.1 ppm silver.

2. Both bullets have a composition highly consistent with WCC/MC bullet lead, although other sources cannot entirely be ruled out.

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line spectrum A type of emission spectrum showing a series of lines separated by black areas; each line represents a definite wavelength or frequency

continuous spectrum A type of emission spectrum showing a continuous band of colors all blending into one another

emission spectrum Light emitted from a source and separated into its component colors or frequencies

INORGANIC ANALYSIS 149

TABLE 6–3 Antimony and Silver Concentrations in the Kennedy Assassination Bullets

Silver (parts

per million)a

Antimony (parts

per million) Sample Description

Q1 8.8 � 0.5 833 � 9 Connally stretcher bullet Q9 9.8 � 0.5 797 � 7 Fragments from Connally’s wrist Q2 8.1 � 0.6 602 � 4 Large fragment from car Q4, 5 7.9 � 0.3 621 � 4 Fragments from Kennedy’s brain Q14 8.2 � 0.4 642 �6 Small fragments found in car

aOne part per million equals 0.0001 percent. Source: Reprinted with permission from V. P. Guinn, “JFK Assassination: Bullet Analyses,” Analytical Chemistry, 51 (1979), 484 A. Copyright 1979, American Chemical Society.

3. The bullet found on the Connally stretcher also damaged Connally’s wrist. The absence of bullet fragments from the back wounds of Kennedy and Connally prevented any effort at linking these wounds to the stretcher bullet.

None of these conclusions can totally verify the Warren Commission’s reconstruction of the assassination, but the results are at least consistent with the commission’s findings. Further, in 2003, an ABC television broadcast showed the results of a ten-year 3-D computer animation study of the events of November 22, 1963. The animation graphically showed that the bullet wounds were completely consistent with Kennedy’s and Governor Connally’s positions at the time of shooting, and that by following the bullet’s trajectory backward they could be found to have originated from a narrow cone including only a few windows of the sixth floor of the School Book Depository.

The analyses on the Kennedy assassination bullets were performed by neutron activation analysis. The remainder of this chapter describes this and other techniques currently used to examine inorganic physical evidence.

The Emission Spectrum of Elements We have already observed that organic molecules can readily be characterized by their selective absorption of ultraviolet, visible, or infrared radiation. Equally significant to the analytical chemist is the knowledge that elements also selectively absorb and emit light. These observations form the basis of two important analytical techniques designed to determine the elemental com- position of materials—emission spectroscopy and atomic absorption spectrophotometry.

Types of Spectra The statement that elements emit light should not come as a total surprise, for one need only observe the common tungsten incandescent lightbulb or the glow of a neon light to confirm this observation. When the light emitted from a bulb or from any other light source is passed through a prism, it is separated into its component colors or frequencies. The resulting display of colors is called an emission spectrum.

When sunlight or the light from an incandescent bulb is passed through a prism, we have already observed that a range of rainbow colors is produced. This emission spectrum is called a continuous spectrum because all the colors merge or blend into one another to form a continu- ous band. However, not all light sources produce such a spectrum. For example, if the light from a sodium lamp, a mercury arc lamp, or a neon light were passed through a prism, the resultant spectrum would consist not of a continuous band but of several individual colored lines separated by dark spaces. Here, each line represents a definite wavelength or frequency of light that is separate and distinct from all others present in the spectrum. This type of spectrum is called a line spectrum. Figure 6–1 shows the line spectra of three elements.

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150 CHAPTER 6

Hydrogen

Helium

Mercury

FIGURE 6–1 Some characteristic emission spectra.

Lens Prism Photographic

plate

Sample between carbon electrodes

FIGURE 6–2 Parts of a simple carbon arc emission spectrograph.

Heated matter in a solid or liquid state produces a continuous spectrum that is not very in- dicative of its composition. However, if this same matter is vaporized and “excited” by exposure to high temperature, each element present emits light composed of select frequencies that are characteristic of the element. This spectrum is in essence a “fingerprint” of an element and offers a practical method of identification. Sodium vapor, for example, always shows the same line spectrum, which differs from the spectrum of all other elements.

Carbon Arc Emission Spectrometry An emission spectrograph is an instrument used to obtain and record the line spectra of elements. Es- sentially, this instrument requires a means for vaporizing and exciting the atoms of elements so that they emit light, a means for separating this light into its component frequencies, and a means of record- ing the resultant spectrum. A simple carbon arc emission spectrograph is depicted in Figure 6–2.

The specimen under investigation is excited when it is inserted between two carbon electrodes through which a direct current arc is passed. The arc produces enough heat to vaporize and excite the specimen’s atoms. The resultant emitted light is collected by a lens and focused onto a prism that disperses it into component frequencies. The separated frequencies are then directed toward a pho- tographic plate, where they are recorded as line images. Normally, a specimen consists of numer- ous elements; hence, the typical emission spectrum contains many lines. Each element present in the spectrum can be identified when it is compared to a standard chart that shows the position of the principal spectral lines of all the elements. However, forensic analysis more commonly requires

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INORGANIC ANALYSIS 151

FIGURE 6–3 A comparison of paint chips 1 and 2 by emission spectrographic analysis. A line-for- line comparison shows that the paints have the same elemental composition.

Sample aerosol

Coil

Ions

++ ++ + +

+ ++

++ +

Rf generator

Plasma discharge

FIGURE 6–4 The creation of charged particles in the torch of an ICP discharge.

simply a rapid comparison of the elemental composition of two or more specimens. This can read- ily be accomplished when the emission spectra are matched line for line, an approach illustrated in Figure 6–3, in which the emission spectra of two paint chips are shown to be comparable.

Inductively Coupled Plasma Emission Spectrometry (ICP) Carbon arc emission spectrometry has been supplanted by inductively coupled plasma (ICP) emission spectrometry. Like the former, ICP identifies and measures elements through light en- ergy emitted by excited atoms. However, instead of using an electrical arc, the atoms are excited by placing the sample in a hot plasma torch. The torch is designed as three concentric quartz tubes through which argon gas flows. A radio frequency (RF) coil that carries a current is wrapped around the tubes. The RF current creates an intense magnetic field.

THE ICP PROCESS The process begins when a high-voltage spark is applied to the argon gas flowing through the torch. This strips some electrons from their argon atoms. These electrons are then caught and accelerated in the magnetic field such that they collide with other argon atoms, stripping off still more electrons. The collision of electrons and argon atoms continues in a chain reaction, breaking down the gas into argon atoms, argon ions, and electrons and forming an inductively coupled plasma discharge. The discharge is sustained by RF energy that is continu- ously transferred to it from the coil. The plasma discharge acts like an intense continuous flame generating extremely high temperatures in the range of 7,000–10,000°C. The sample, in the form of an aerosol, is then introduced into the hot plasma, where it collides with the energetic argon electrons generating charged particles (ions) that emit light of characteristic wavelengths corre- sponding to the identity of the elements present (see Figure 6–4).

APPLICATIONS OF ICP Two areas of forensic casework in which ICP has been applied are the identification and characterization of mutilated bullets1 and glass fragments.2 Mutilated bullets often are not suitable for traditional microscopic comparisons against an exemplar test-fired bullet. In such situations, ICP has been used to obtain an elemental profile of the questioned bullet fragment

1 R. D. Koons and J. Buscaglia, “Forensic Significance of Bullet Lead Compositions,” Journal of Forensic Sciences 50 (2005): 341.

2 S. Montero, A. L. Hobbs, T. A. French, and J. Almirall, “Elemental Analysis of Glass Fragments by ICP-MS as Evidence of Association: Analysis of a Case,” Journal of Forensic Sciences 48 (2003): 1101.

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152 CHAPTER 6

Acetylene AirLiquid sample

Hollow cathode tube

Flame

Monochromator

Detector Recorder

FIGURE 6–5 Parts of a simple flame atomic absorption spectrophotometer.

for comparison against an unfired bullet generally found in the possession of the suspect. For a num- ber of years forensic scientists have taken advantage of significant compositional differences among lead sources for the manufacture of lead-based bullets. Compositional differences in the trace ele- ments that constitute lead bullets are typically reflected in the copper, arsenic, silver, antimony, bis- muth, cadmium, and tin profiles of lead bullets. When two or more bullets have comparable elemental compositions, evidence of their similarity may be offered in a court of law.

In this respect, the comparison of lead bullets faces the same quandary as most common types of class physical evidence—how can a forensic analyst explain to a jury that such a finding has meaningful consequences to a criminal inquiry without being able to provide statistical or prob- ability data to support such a contention? Furthermore, the creation of meaningful databases to statistically define the significance of bullets compared by their elemental profiles is currently an unrealistic undertaking. Nevertheless, the significant diversity of bullet lead compositions in our population, like other class evidence such as fibers, hairs, paint, plastics, and glass, makes their chance occurrence at a crime scene and subsequent link to a defendant a highly unlikely event. However, care must be taken to avoid giving the trier of fact the impression that elemental pro- files constitute a definitive match. Given the millions of bullets produced each year, one cannot conclusively rule out the possibility of a coincidental match with a non-case-related bullet.

Atomic Absorption Spectrophotometry When an atom is vaporized, it absorbs many of the same frequencies of light that it emits in an excited state. The selective absorption of light by atoms is the basis for a technique known as atomic absorption spectrophotometry. A simple atomic absorption spectrophotometer is illus- trated in Figure 6–5.

The Spectrophotometry Process In atomic absorption spectrophotometry, the specimen is heated to a temperature that is hot enough to vaporize its atoms while leaving a substantial number of atoms in an unexcited state. Normally, the specimen is inserted into an air-acetylene flame to achieve this temperature. The vaporized atoms are then exposed to radiation emitted from a light source. The technique achieves great specificity by using as its radiation source a discharge tube made of the same element being analyzed in the speci- men. When the discharge lamp is turned on, it emits only the frequencies of light that are present in the emission spectrum of the element. Likewise, the sample absorbs these frequencies only when it contains the same element. Therefore, to determine the presence of antimony in a specimen, the atomic absorption spectrophotometer must be fitted with a discharge lamp that is constructed of an- timony. Under these conditions, the sample will absorb light only when it contains antimony.

Once the radiation has passed through the sample, a monochromator, consisting of a prism or a diffraction grating and a slit, isolates the desired radiation frequency and transmits it to a detector. The detector converts the light into an electrical signal, the intensity of which is observed on a digital recorder.

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nucleus The core of an atom containing the protons and neutrons

electron A negatively charged particle that is one of the fundamental structural units of the atom

proton A positively charged particle that is one of the basic structures in the nucleus of an atom

INORGANIC ANALYSIS 153

The absorption of light by the element of interest is the phenomenon that is being measured in atomic absorption spectrophotometry. The concentration of the absorbing element is directly pro- portional to the quantity of the light absorbed. The higher the concentration of the element, the more light is absorbed. For this reason, atomic absorption spectroscopy is most useful for accurately determining an element’s concentration in a sample. Furthermore, the technique is sufficiently sen- sitive to find wide application in detecting and quantitating elements that are present at trace levels. However, the technique does have one drawback in that the analyst can determine only one element at a time, each time having to select the proper lamp to match the element under investigation.

Applications of Spectrophotometry Although atomic absorption spectrophotometry has been used for chemical analysis since 1955, it has not yet found wide application for solving forensic problems. However, a modification in the design of the instrument promises to change this situation. By substituting a heated graphite furnace or a heated strip of metal (tantalum) for the flame, analysts have achieved a more efficient means of atomic volatilization and as a result have substantially increased the sensitivity of the technique. Many elements can now be detected at levels that approach one-trillionth of a gram.

The high sensitivity of “flameless” atomic absorption now equals or surpasses that of most known analytical procedures. Considering the relative simplicity and low cost of the technique, atomic absorption spectrophotometry has become an attractive method for detecting and meas- uring the smallest levels of trace elements present in physical evidence.

The Origin of Emission and Absorption Spectra Any proposed theory that attempts to explain the origin of emission and absorption spectra must relate to the fundamental structure of the element—the atom. Scientists now know that the atom is composed of even more elementary particles that are collectively known as subatomic parti- cles. The most important subatomic particles are the proton, electron, and neutron. The masses of the proton and neutron are each about 1,837 times the mass of an electron. The proton has a positive electrical charge; the electron has a negative charge equal in magnitude to that of the proton; and the neutron is a neutral particle having neither a positive nor a negative charge. The properties of the proton, neutron, and electron are summarized in the following table:

3 Actually, the electrons are moving so rapidly around the nucleus as to best be visualized as being in the form of an electron cloud spread out over the surface of the atom.

neutron A particle with no electrical charge that is one of the basic structures in the nucleus of an atom

Particle Symbol Relative Mass Electrical Charge

Proton P 1 �1 Neutron n 1 0 Electron e 1/1,837 �1

Atomic Structure A popular descriptive model of the atom, and the one that will be adopted for the purpose of this discussion, pictures an atom as consisting of electrons orbiting around a central nucleus—an image that is analogous to our solar system, in which the planets revolve around the sun.3 The nucleus of the atom is composed of positively charged protons and neutrons that have no charge. Because the atom has no net electrical charge, the number of protons must always be equal to the number of negatively charged electrons in orbit around the nucleus.

With this knowledge, we can now begin to describe the atomic structure of the elements; for example, hydrogen has a nucleus consisting of one proton and no neutrons, and it has one orbiting electron. Helium has a nucleus comprising two protons and two neutrons, with two electrons in orbit around the nucleus (see Figure 6–6).

The behavior and properties that distinguish one element from another must be related to the dif- ferences in the atomic structure of each element. One such distinction is that each element possesses

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excited state The state in which an atom absorbs energy and an electron moves from a lower to a higher energy level

atomic number The number of protons in the nucleus of an atom; each element has its own unique atomic number

154 CHAPTER 6

(a) (b)

FIGURE 6–7 (a) The absorption of light by an atom, causing an electron to jump into a higher orbital. (b) The emission of light by an atom, caused by an electron falling back to a lower orbital.

a different number of protons. This number is called the atomic number of the element. As we look back at the periodic table illustrated in Figure 5–1, we see that the elements are numbered consecu- tively. Those numbers represent the atomic number or number of protons associated with each ele- ment. An element is therefore a collection of atoms that all have the same number of protons. Thus, each atom of hydrogen has one and only one proton, each atom of helium has 2 protons, each atom of silver has 47 protons, and each atom of lead has 82 protons in its nucleus.

Electron Orbitals To explain the origin of atomic spectra, our attention must now focus on the electron orbitals of the atom. As electrons move around the nucleus, they are confined to a path from which they can- not stray. This orbital path is associated with a definite amount of energy and is therefore called an energy level. Each element has its own set of characteristic energy levels at varying distances from the nucleus. Some levels are occupied by electrons; others are empty.

An atom is in its most stable state when all of its electrons are positioned in their lowest possi- ble energy orbitals in the atom. When an atom absorbs energy, such as heat or light, its electrons are pushed into higher-energy orbitals. In this condition, the atom is in an excited state. However, be- cause energy levels have fixed values, only a definite amount of energy can be absorbed in moving an electron from one level to another. This is a most important observation, for it means that atoms absorb only a definite value of energy, and all other energy values will be excluded. In atomic ab- sorption spectrophotometry, a photon of light interacts with an electron, causing it to jump into a higher orbital, as shown in Figure 6–7(a). A specific frequency of light is required to cause this tran- sition, and its energy must correspond to the exact energy difference between the two orbitals in- volved in the transition. This energy difference is expressed by the relationship E � hf, where E represents the energy difference between the two orbitals, f is the frequency of absorbed light, and h is a universal constant called Planck’s constant. Any energy value that is more or less than this dif- ference will not produce the transition. Hence, an element is selective in the frequency of light it will absorb, and this selectivity is determined by the electron energy levels each element possesses.

In the same manner, if atoms are exposed to intense heat, enough energy is generated to push electrons into unoccupied higher-energy orbitals. Normally, the electron does not remain in this excited state for long, and it quickly falls back to its original energy level. As the electron falls back, it releases energy. An emission spectrum testifies to the fact that this energy loss comes about in the form of light emission [see Figure 6–7(b)]. The frequency of light emitted is again determined by the relationship E � hf, where E is the energy difference between the upper and lower energy levels and f is the frequency of emitted light. Because each element has its own characteristic set of energy levels, each emits a unique set of frequency values. The emission spectrum thus provides a “picture” of the energy levels that surround the nucleus of each element.

Thus, we see that as far as atoms are concerned, energy is a two-way street. Energy can be put into the atom at the same time that energy is given off; what goes in must come out. The chemist can study the atom using either approach. Atomic absorption spectrophotometry carefully measures the value and amount of light energy going into the atom; emission spectroscopy collects and measures

1P

Hydrogen

2P 2n

Helium

FIGURE 6–6 The atomic structures of hydrogen and helium.

electron orbital The path of electrons as they move around the nuclei of atoms; each orbital is associated with a particular electronic energy level

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isotope An atom differing from another atom of the same element in the number of neutrons in its nucleus

atomic mass The sum of the number of protons and neutrons in the nucleus of an atom

INORGANIC ANALYSIS 155

the various light energies given off. The result is the same: atoms are identified by the existence of characteristic energy levels.

Neutron Activation Analysis Once scientists realized that it was possible to change the number of subatomic particles in the atom’s nucleus, the unleashing of a new source of energy—nuclear energy—was inevitable. This energy has proven so awesome in its power that the survival of civilization will depend on our ability to refrain from using its destructive forces. Of course, this threat does not obscure the fact that controlled nuclear energy promises to be a source of power capable of relieving our depend- ency on the earth’s dwindling reserves of fossil fuels. For the chemist, nuclear chemistry provides a new tool for identifying and quantitating the elements.

Isotopes Until now, our discussion of subatomic particles has been limited to the proton and electron. How- ever, to understand the principles of nuclear chemistry, we must look at the other important subatomic particle, the neutron. Although the atoms of a single element must have the same number of protons, nothing prevents them from having different numbers of neutrons. The total number of protons and neutrons in a nucleus is known as the atomic mass number.

Atoms with the same number of protons but differing solely in the number of neutrons are called isotopes. For example, hydrogen consists of three isotopes; besides ordinary hydrogen, which has one proton and no neutrons, two other isotopes exist, deuterium and tritium. Deuterium (or heavy hydrogen) also has one proton but contains one neutron as well. Tritium has one pro- ton and two neutrons in its nucleus. The atomic structures of these isotopes are shown in Figure 6–8. Therefore, all the isotopes of hydrogen have an atomic number of 1 but differ in their atomic mass numbers. Hydrogen has an atomic mass number of 1, deuterium a mass of 2, and tritium a mass of 3. Ordinary hydrogen makes up 99.98 percent of all the hydrogen atoms found in nature.

Radioactivity Like hydrogen, most elements are known to have two or more isotopes. Tin, for example, has ten isotopes. Many of these isotopes are quite stable, and for all intents and purposes, the isotopes of any one element have indistinguishable properties. Others, however, are not as stable and decompose with time by a process known as radioactive decay. Radioactivity is the emission of radiation that accompanies the spontaneous disintegration of unstable nuclei. Radioactivity is actually composed of three types of radiation: alpha particles, beta particles, and gamma rays.

Alpha particles are positively charged particles, each with a mass approximately four times that of a hydrogen atom. These particles are helium atoms stripped of their orbiting electrons. Beta particles are actually electrons, and gamma rays are electromagnetic radiations similar to X-rays but of a higher frequency and energy (refer to the electromagnetic spectrum in Figure 5–15). Fortunately, most naturally occurring isotopes are not radioactive, and those that are—radium, uranium, and thorium—are found in such small quantities in the earth’s crust that their radioactivity presents no hazard to human survival.

Because of their large mass, alpha particles do not tend to travel far and are not very pene- trating; a sheet of paper or your skin easily stops them. However, radioisotopes that emit alpha

gamma ray A high-energy form of electromagnetic radiation emitted by a radioactive element

beta particle A type of radiation emitted by a radioactive element; the radiation consists of electrons

alpha particle A type of radiation emitted by a radioactive element; the radiation is composed of helium atoms minus their orbiting electrons

radioactivity The particle and/or gamma-ray radiation emitted by the unstable nucleus of some isotopes

Hydrogen Deuterium Tritium

1P 1P 1n

1P 2n

FIGURE 6–8 Isotopes of hydrogen.

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156 CHAPTER 6

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y Death by Radiation Poisoning In November 2006, Alexander V. Litvinenko lay at death’s door in a London hospital. He was in excruciating pain and had symp- toms that included hair loss, the inability to make blood cells, and gastrointestinal distress. His organs slowly failed as he lingered for three weeks and then died. British investigators soon con- firmed that Litvinenko died from the intake of polonium-210, a radioactive element, in what appeared to be its first use as a murder weapon (see Figure 1).

Litvinenko’s death almost immediately set off an interna- tional uproar. Litvinenko, a former KGB operative, had be- come a vocal critic of the Russian spy agency FSB, the domestic successor to the KGB. In 2000, he fled to London where he was granted asylum. Litvinenko continued to voice his criticisms of the Russian spy agency and also became highly critical of Russia’s president, Vladimir Putin. Just be- fore his death, he was believed to have compiled, on behalf of a British company looking to invest millions in a project in Russia, an incriminating report regarding the activities of sen- ior Kremlin officials.

Suspicions immediately fell onto Andrei Lugovoi and Dmitri Kovtun, business associates of Mr. Litvinenko. Lugovoi was himself a former KGB officer. On the day he fell ill, Litvinenko met Lugovoi and Kovtun at the Pine Bar of the Millennium Hotel in London. At the meeting, Mr. Litvinenko drank tea out of a teapot later found to be highly radioactive. British officials have accused Lugovoi of

FIGURE 1 Alexander Litvinenko, former KGB agent, before and after he became sick. (left) Courtesy AP Wide World Photos (right) Courtesy Getty Images, Inc.-Getty News

poisoning Litvinenko. The precise nature of the evidence against him has not been made clear, though investigators have linked him and Mr. Kovtun to a trail of polonium-210 radioactivity stretching from hotel rooms, restaurants, bars, and offices in London to Hamburg, Germany, and to British Airways planes that had flown to Moscow. Each man has denied killing Mr. Litvinenko.

Polonium-210 is highly radioactive and very toxic. By weight, it is about 250 million times as toxic as cyanide, so a particle the size of a dust particle could be fatal. It emits a radioactive ray known as an alpha particle. This form of radiation cannot penetrate the skin, so polonium-210 is effective as a poison only if it is swallowed, breathed in, or injected. The particles disperse through the body and first destroy fast-growing cells, like those in bone marrow, blood, hair, and the digestive tract. That would be consistent with Mr. Litvinenko’s symptoms. There is no antidote for polo- nium poisoning.

Polonium does have industrial uses and is produced by commercial or institutional nuclear reactors. Polonium-210 has been found to be ideal for making antistatic devices that remove dust from film and lenses as well as paper and textile plants. Its non-body-penetrating rays produce an electric charge on nearby air. Bits of dust with static attract the charged air, which neutralizes them. Once free of static, the dust is easy to blow or brush away. Manufacturers of such antistatic devices take great pains to make the polonium hard to remove from their products.

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INORGANIC ANALYSIS 157

rays are dangerous when ingested. The radioisotope polonium-210, an emitter of alpha particles, was recently implicated in the murder of an ex-KGB agent (see the case study below).

The existence of isotopes would be of little importance to the forensic chemist were it not for the fact that scientists have mastered the techniques for synthesizing radioactive isotopes. If the only distinction between isotopes of an element is the number of neutrons each possesses, is it not reasonable to assume that when atoms are bombarded with neutrons, some neutrons will be captured to make new isotopes? This is exactly what happens in a nuclear reactor. A nuclear reactor is simply a source of neutrons that can be used to bombard the atoms of a specimen, thereby creating radioactive isotopes. When the nucleus of an atom captures a neutron, a new iso- tope with one additional neutron is formed. In this state, the nuclei are said to be activated, and many immediately begin to decompose by emitting radioactivity.

The Process of Neutron Activation Analysis To identify the activated isotope, it is necessary to measure the energy of the gamma rays emitted as radioactivity. The gamma rays of each element can be associated with a characteristic energy value. Furthermore, once the element has been identified, its concentration can be measured by the intensity of its gamma-ray radiation; intensity is directly proportional to the concentration of the element in a specimen. The technique of bombarding specimens with neutrons and measur- ing the resultant gamma-ray radioactivity is known as neutron activation analysis. The process is depicted in Figure 6–9.

The major advantage of neutron activation analysis is that it provides a nondestructive method for identifying and quantitating trace elements. A median detection sensitivity of one- billionth of a gram (one nanogram) makes neutron activation analysis one of the most sensitive methods available for the quantitative detection of many elements. Further, neutron activation can simultaneously analyze 20 to 30 elements. A major drawback to the technique is its expense

Atom

n

n

n

Neutron

Neutrons bombard specimen

Atom

n

n

Neutron

Energy

In te

ns ity

Energy

In te

ns ity

Energy

In te

ns ity

Detector measures the energies and intensities of the gamma rays

Multichannel analyzer

Each element is associated with a characteristic energy value. Intensity indicates the element concentration in the specimen

Atom

Gamma Rays

Gamma Rays

FIGURE 6–9 The neutron activation process requires the capture of a neutron by the nucleus of an atom. The new atom is now radioactive and emits gamma rays. A detector permits identification of the radioactive atoms present by measuring the energies and intensities of the gamma rays emitted.

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158 CHAPTER 6

TABLE 6–4 Concentration of Trace Elements in Copper Wire

Selenium Gold Antimony Silver

Control Wire

A1 2.4 0.047 0.16 12.7 A2 3.5 0.064 0.27 17.2 A3 2.6 0.050 0.20 13.3 A4 1.9 0.034 0.21 12.6

Suspect Wire

B 2.3 0.042 0.15 13.0

Note: Average concentration measured in parts per million.

Source: R. K. H. Chan, “Identification of Single-Stranded Copper Wires by Nondestructive Neutron Activation Analysis,” Journal of Forensic Sciences 17 (1972), 93. Reprinted by permission of the American Society for Testing and Materials, copyright 1972.

and regulatory requirements. Only a handful of crime laboratories worldwide have access to a nuclear reactor; in addition, sophisticated analyzers are needed to detect and discriminate gamma-ray emissions.

Applications of Neutron Activation Analysis As far as forensic analysis is concerned, neutron activation has been used to characterize trace el- ements present in metals, drugs, paint, soil, gunpowder residues, and hair. A typical illustration of its application occurred during the investigation of a theft of copper telegraphic wires in Canada. Four lengths of copper wire (A1, A2, A3, A4) found at the scene of the theft were compared by neu- tron activation with a length of copper wire (B) seized at a scrap yard and suspected of being stolen. All were bare, single-strand wire with the same general physical appearance and a diameter of 0.28 centimeter. Prior experiments had revealed that significant variations could be expected in the concentration levels of the trace elements selenium, gold, antimony, and silver for wires originat- ing from different sources. A comparison of these elements present in the wire involved in the theft was undertaken. After exposing the wires to neutrons in a nuclear reactor, neutron activation analysis revealed a match between A1 and B that was well within experimental error (see Table 6–4). The findings suggested a common origin of the control and suspect wires.

X-Ray Diffraction Until now, we have discussed methods for detecting and identifying the elements. Emission spec- troscopy, atomic absorption, and neutron activation analysis tell us what elements are present in a particular substance, but they do not provide any information as to how the elements are com- bined into compounds. One way to elicit this information is to aim a beam of X-rays at a crystal and study how the X-rays interact with the atoms that compose the substance under investigation. This technique is known as X-ray diffraction.

X-ray diffraction can be applied only to the study of solid, crystalline materials—that is, solids with a definite and orderly arrangement of atoms. For example, sodium chloride (common table salt), pictured in Figure 4–8, is crystalline. Fortunately, many substances, including 95 percent of all inorganic compounds, are crystalline and thus identifiable by X-ray diffraction analysis. The atoms in a crystal can be thought of as being composed of a series of parallel planes. As the X-rays penetrate the crystal, a portion of the beam is reflected by each of the atomic planes. As the reflected beams leave the crystal’s planes, they combine with one another to form a series of light and dark bands known as a diffraction pattern. Every compound produces a unique diffraction pattern, thus giving analysts a means for “fingerprinting” compounds.

A diagram depicting the X-ray diffraction process is illustrated in Figure 6–10. Diffraction patterns for potassium nitrate and potassium chlorate, two common constituents of homemade explosives, are shown in Figure 6–11. Comparing a questioned specimen with a known X-ray pattern is a rapid and specific way to prove chemical identity.

X-ray diffraction An analytical technique for identifying crystalline materials

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One drawback to X-ray diffraction is its lack of sensitivity. The technique is suitable for iden- tifying the major constituents of a mixture, but it often fails to detect the presence of substances constituting less than 5 percent of a mixture. For this reason, the forensic chemist must use more sensitive techniques—emission spectroscopy, atomic absorption, and neutron activation analy- sis—to identify trace elements that may be present.

INORGANIC ANALYSIS 159

Photographic plate

FIGURE 6–10 A beam of X-rays being reflected off the atomic planes of a crystal. The diffraction patterns that form are recorded on photographic film. These patterns are unique for each crystalline substance.

(a)

FIGURE 6–11 X-ray diffraction patterns for (a) potassium nitrate and (b) potassium chlorate.

(b)

sampling airborne particles from the country’s nuclear bomb tests. Nuclear forensics matured as a science when the Soviet empire disintegrated and concerns arose over the security of nuclear materials located in states of the former Soviet Union. Fears that these materials might fall into the hands of terrorist organizations engendered scenarios of dirty nuclear bombs attacks on the United States and other Western nations.

Nuclear forensics is becoming an increasingly important tool in the fight against illegal smuggling

fo re

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Nuclear forensics has emerged as a critical pro- fession on the forefront in the war on terrorism. Nuclear forensic scientists are responsible for developing ways to analyze nuclear materials recovered from either intercepted intact nuclear materials or postexplosion debris created as a result of a nuclear explosion. Nuclear forensics can trace its origin to the cold war era, when U.S. planes surreptitiously flew over Soviet airspace

(Continued)

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160 CHAPTER 6 fo

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> > > > > > > > > > > > > > > > > and trafficking of radiological and nuclear materi- als. These include materials intended for industrial and medical use, nuclear materials such as those produced in the nuclear fuel cycle of a nuclear power plant (see Figure 1), and much more dan- gerous nuclear materials that can be used in weapons, such as plutonium and highly enriched uranium. Since the early 1990s, more than two hun- dred cases of illicitly trafficked nuclear materials have been reported.

In the United States, Lawrence Livermore National Laboratory along with seven other Department of Energy (DOE) national laboratories have been tasked by the FBI and the Department of Homeland Security with developing the nation’s technical forensics capability for nuclear and radiological materials. Organizations such as the European Commission’s Institute for Transuranium Elements located in Karlsruhe, Germany, have extend nuclear forensic capabilities onto an inter- national scale.

A major focus of nuclear forensics is identifying signatures, which are the physical, chemical, and isotopic characteristics that distinguish one nuclear or radiological material from another. Signatures enable researchers to identify the processes used to initially create a material, which ultimately may yield clues as to the origin of the seized material.

Nuclear forensics can be performed on a broad spec- trum of substances. An example is stolen containers of uranium diverted during one of the mining, milling, conversion, enrichment, or fuel fabrication steps used to convert uranium ore to enriched fuel for nuclear power plants; uranium varies in isotopic composition and impurities according to where the uranium was mined and how it was processed. An- other example is commercial radioactive materials used in applications such as medical diagnostics and food sterilization.

Researchers analyze the material’s chemical and isotopic composition, which includes measur- ing the amounts of trace elements as well as the ratio of parent isotopes to daughter isotopes. These measurements help determine the source location and sample’s age. They also examine the material’s morphological characteristics such as shape, size, and texture. Analytical methods include electron microscopy, X-ray diffraction, and mass spectrometry. In addition, as a sample is moved from place to place, it picks up trace evidence such as pollen, hairs, fibers, plant DNA, and fingerprints. These so-called route materials may provide infor- mation about who has handled a sample and the path it has traveled.

When comparing a sample’s signature against known signatures from uranium mines and fabri- cation plants, researchers can benefit by assem- bling a library of nuclear materials of known origin from around the world. Nuclear scientists have developed relationships with domestic suppliers of nuclear materials to assemble such a library. Contracts with major U.S. uranium fuel suppliers have provided researchers with samples and manufacturing data. Forensic scientists are also seeking to obtain samples of uranium products worldwide to analyze the products’ isotopic and trace-element content, grain size, and microstruc- ture. Nations with nuclear capabilities are begin- ning to share information about their nuclear fuel processes and materials. The development of databases is essential to the nuclear forensic scientist’s mission of identifying the origin of nuclear materials intercepted in the black market or associated with a terrorist event.

Nuclear Forensics (continued)

Figure 1 © Royalty-Free/CORBIS

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INORGANIC ANALYSIS 161

review questions

1. The elements ___________ and ___________ make up 75 percent of the weight of the earth’s crust.

2. Only ___________ elements make up about 99 percent of the weight of the earth’s crust.

3. The presence of ___________ elements in materials pro- vides useful “invisible” markers when comparing phys- ical evidence.

4. The knowledge that elements selectively ___________ and ___________ light provides the basis for important analytical techniques designed to detect the presence of elements in materials.

5. A(n) ___________ is a display of colors or frequencies emitted from a light source.

6. True or False: A continuous spectrum consists of a blend- ing of colors. ___________

7. A(n) ___________ spectrum shows distinct frequencies or wavelengths of light.

8. A line spectrum of an element (is, is not) characteristic of the element.

9. True or False: Matter in a solid or liquid state pro- duces an emission spectrum that is characteristic of its composition. ___________

10. The ___________ is an instrument used to obtain and record the line spectrum of elements.

11. Excitation of a specimen can be accomplished when it is inserted between two ___________ electrodes.

12. The selective absorption of light by atoms is the basis for a technique known as ___________.

13. The composition of the discharge lamp (does, does not) have to be taken into consideration when per- forming an analysis by atomic absorption for a partic- ular element.

14. True or False: One advantage of atomic absorption analysis is that it can simultaneously detect 20 to 30 elements. ___________

15. Three important subatomic particles of the atom are the ___________, ___________, and ___________.

chapter summary

Inorganic substances are encountered by forensic scientists as tools, explosives, poisons, and metal scrapings as well as trace components in paints and dyes. Many manufactured products and even most natural materials contain small quantities of elements in concentrations of less than 1 percent. For the crim- inalist, the presence of these trace elements is particularly use- ful because they provide “invisible” markers that may establish the source of a material or at least provide additional points for comparison.

Emission spectroscopy, inductively coupled plasma, and atomic absorption spectrophotometry are three techniques available to forensic scientists for determining the elemental composition of materials. An emission spectrograph vaporizes and heats samples to a high temperature so that the atoms pres- ent in the material achieve an “excited” state. Under these cir- cumstances, the excited atoms emit light. If the light is separated into its components, one observes a line spectrum. Each element present in the spectrum can be identified by its characteristic line frequencies. In inductively coupled plasma, the sample, in the form of an aerosol, is introduced into a hot plasma, creating charged particles that emit light of characteristic wavelengths corresponding to the identity of the elements present.

In atomic absorption spectrophotometry, the specimen is heated to a temperature that is hot enough to vaporize its atoms while leaving a substantial number of atoms in an unexcited state. The vaporized atoms are then exposed to radiation emitted from a light source specific for a particular element. If the element is present in the material under investigation, a portion of the light is absorbed by the substance. In this manner, many elements can be detected at levels that ap- proach one-trillionth of a gram. Neutron activation analysis measures the gamma-ray frequencies of specimens that have been bombarded with neutrons. This method provides a highly sensitive and nondestructive analysis for simultaneously iden- tifying and quantitating 20 to 30 trace elements. Because this technique requires access to a nuclear reactor, however, it has limited value to forensic analysis.

X-ray diffraction is used to study solid, crystalline materi- als. As the X-rays penetrate the crystal, a portion of the beam is reflected by each atomic plane. As the reflected beams leave the crystal’s planes, they combine with one another to form a series of light and dark bands known as a diffraction pattern. Every compound produces a unique diffraction pattern, thus giving analysts a means for “fingerprinting” inorganic compounds.

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application and critical thinking

1. A forensic analyst at the local crime lab receives pieces of a disfigured bullet from a crime scene. He or she then obtains an exemplar bullet fired by the firearms analyst from the suspect’s firearm. What is the next step in analysis?

2. Only a handful of crime laboratories worldwide have ac- cess to a nuclear reactor to carry out neutron activation analysis. What are some possible reasons why this is so?

3. If a forensic analyst wanted to analyze a particular sam- ple for the presence of trace amounts of an inorganic sub- stance, would X-ray diffraction be a suitable analytical tool? Why or why not?

further references

Forensic Analysis: Weighing Bullet Lead Evidence. Washington, D.C.: National Academies Press, 2004.

Guinn, V. P., “The Elemental Comparison of Bullet-Lead Evidence Specimens,” in S. M. Gerber, ed., Chemistry and Crime. Washington, D.C.: American Chemical Society, 1983.

Houck, Max M., ed., Mute Witnesses: Trace Evidence Analy- sis. Burlington, Mass.: Elsevier Academic Press, 2001.

Houck, Max M., ed., Trace Evidence Analysis—More Cases in Mute Witnesses. Burlington, Mass.: Elsevier Academic Press, 2004.

Settle, F. A., ed., Handbook of Instrumental Techniques for Analytical Chemistry. Upper Saddle River, N.J.: Prentice Hall, 1998.

16. The proton and electron (are, are not) of approximately equal mass.

17. A proton imparts the nucleus of an atom with a ___________ charge.

18. The number of protons (is, is not) always equal to the number of electrons in orbit around the nucleus of an atom.

19. Each atom of the same element always has the same number of ___________ in its nucleus.

12 Repaying Victims

CHAPTER OUTLINE The Costs of Victimizations

Gaining Restitution from Offenders

Back to Basics The Rise, Fall, and Rediscovery of Restitution Divergent Goals, Clashing Philosophies Opportunities to Make Restitution Obstacles Undermining Restitution Restitution in Action

Winning Judgments in Civil Court

The Revival of Interest in Civil Lawsuits The Litigation Process Collecting Damages from Third Parties

Collecting Insurance Reimbursements

Private Crime Insurance Patterns of Loss, Recovery, and Reimbursement Federal Crime Insurance

Recovering Losses through Victim Compensation Programs

The History of Victim Compensation by Governments The Debate over Compensation in the United States How Programs Operate: Similarities and Differences Monitoring and Evaluating Compensation Programs

Confiscating Profits from Notorious Criminals Writing and Rewriting the Law

Summary Key Terms Defined in the Glossary Questions for Discussion and Debate Critical Thinking Questions Suggested Research Projects

LEARNING OBJECTIVES To recognize the many individual and social costs

imposed by criminal activities.

To develop a familiarity with the different ways that injured parties can get reimbursed for their losses.

To understand the various rationales for imposing restitution obligations on offenders.

To become familiar with the arguments in favor of and in opposition to state-run compensation funds.

To recognize the opportunities and drawbacks of civil lawsuits.

To identify the limitations of insurance coverage as a means of recovery.

To appreciate the reasons for favoring and for opposing notoriety-for-profit laws.

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The costs of victimizations cannot be measuredsolely in monetary terms. Mental anguish and physical suffering cannot easily be translated into dollars and cents. Nevertheless, repairing the dam- age to a victim’s financial standing is an achievable goal and a necessary step toward recovery.

Out-of-pocket expenses can be regained in many ways. Making the offender pay is everyone’s first choice, as it embodies the most elemental notion of justice. In criminal court, judges can order con- victs to make restitution, generally as a condition of either probation or parole. Insurance coverage also can be a source of repayment. In some cases, financial aid can be forthcoming from a government-run state compensation fund set up to cover certain crime- related expenses. Note that restitution and compen- sation are alternative methods of repaying losses. Restitution is the responsibility of blameworthy offenders. Compensation comes from blameless third parties, either government-run funds or private insurance companies. In civil court, judges and juries can compel wrongdoers to pay monetary damages. Another possible source of reparations might come in the form of a civil court judgment against a grossly negligent third party, such as a commercial enterprise or a governmental agency that is considered to bear some responsibility for the criminal incident. Finally, in rare instances, victims might be able to deprive offenders of any profits gained from selling a sensa- tionalized “inside story” of their shocking exploits.

This chapter explores all of these means of eco- nomic recovery: court-ordered restitution, lawsuits for damages, third-party civil suits, private insurance policies, government compensation plans, and leg- islation prohibiting criminals from cashing in on their notoriety.

THE COSTS OF VICTIMIZATIONS

The social costs of crime-related expenditures are staggering, according to economists’ estimates. Vic- tims sustain economic losses whenever offenders take cash or valuables; steal, vandalize, or destroy property; and inflict injuries that require medical attention and recuperation that interferes with

work. Theft and fraud bring about the direct trans- fer of wealth from victims to criminals. Murders terminate lives prematurely, resulting in lost earn- ings for devastated family members. Nonfatal wounds trigger huge expenses for medical care— bills from doctors, emergency rooms, hospitals, pharmacies, nursing services, occupational thera- pists, and dentists. The old saying, “It’s only money” might underestimate how even modest losses from a robbery or theft can impose serious hardships for individuals living from paycheck to paycheck, as this case demonstrates:

A knife-wielding robber steals the purse and jewelry of a retired woman scraping by on disability payments. It takes at least six weeks to replace the ID cards and Social Security check in her stolen wallet. In the meantime, she has no cash, no bus pass, and no way to pay for her many prescription drugs, or even dog food for her pet. None of the social service agencies on the list provided by the big city police department offers emergency financial assistance. Finally, she discovers a faith-based charity that is willing to pay her rent and electric bill and give her food vouchers and $50 in cash. “If not for them, I could not have gotten my heart medication, and I’d be going to bed hungry,” she tells a reporter. (Kelley, 2008)

Serious injuries may also inflict emotional suf- fering that requires psychological care for intense feelings of fear, grief, anger, confusion, guilt, and shame. Possible long-term consequences include mental illness and suicide, as well as alcohol and drug abuse. Some may get their lives back in order rather quickly, but others could be haunted by disturbing memories and burdened by phobias and by post-traumatic stress disorder (PTSD) for long periods of time. Overall, the lifetime risk of developing PTSD for violent crime victims is much higher than for the general public. Rates of experiencing episodes of major depression and gen- eralized anxiety are also greater. Furthermore, the effects of the victims’ emotional turmoil are likely to spill over on to family members, close friends, even neighbors. An outbreak of crime can have a

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negative impact on an entire community, fostering a fear of strangers, undermining involvement in activities outside the home, eroding a sense of cohesiveness, and driving out some of the most productive residents (Herman and Waul, 2004).

Even those who are not directly connected to the injured parties may suffer a “psychic toll” from the ever-present fear that permeates a crime-ridden community. The result is that people are willing to pay substantial amounts of money in the form of taxpayer-funded government actions plus private expenditures in their search for greater security and an improved quality of life. Expenses arise from the crime-induced production of goods and services that would not be necessary if illegal activities were not such a grave problem. For exam- ple, the time, money, and resources spent on manufacturing protective devices (locks, surveil- lance cameras, and alarm systems) are crime- induced outlays, as are private security forces and theft insurance. Similarly, local, state, and federal government funds are consumed pursuing “the war on crime,” “the war on drugs,” and the “war on terror.” That translates into huge expenditures for investigating illegal activities by law enforce- ment agencies, and running court and prison sys- tems (including prosecutors’ offices, indigent defense, incarceration, treatment programs, proba- tion, and parole). All of these governmental expen- ditures can be considered to be a net loss of productive resources to society. If the risks to life and health from criminal activity were not so great, these corporate, governmental, taxpayer, and per- sonal expenditures could have been used to meet basic needs and improve living standards for the law-abiding majority (Anderson, 1999).

Some studies that attempt to estimate the costs of crimes focus on what victims lose, but others high- light how much “society” loses when an offender becomes enmeshed in a criminal career. For exam- ple, one group of researchers projected that every murder of an adult (in Pennsylvania in the late 1990s) cost the entire society about $3.5 million. Another group of researchers devised a formula for monetizing a criminal career in order to determine its “external costs” to others over a lifetime, and came

up with even larger estimated societal outlays. For example, each murder inflicted about $4.7 million in victim costs, over $300,000 in justice system expenditures, and nearly $150,000 in offender pro- ductivity losses, for a total cost of over $5 million. Each armed robbery imposed costs of nearly $50,000, and the average burglary inflicted losses of about $5,500 (De Lisi et al., 2010).

GAINING RESTITUTION FROM OFFENDERS

Back to Basics

A renewed interest in restitution developed during the 1970s. Restitution takes place whenever injured parties are repaid by the individuals who are directly responsible for their losses. Offenders return stolen goods to their rightful owners, hand over equiva- lent amounts of money to cover out-of-pocket expenses, or perform direct personal services to those they have harmed. Community service is a type of restitution designed to make amends to society as a whole. Usually it entails offenders working to “right some wrongs,” repairing the damage they are responsible for, cleaning up the mess they made, or laboring in order to benefit some worthy cause or group. Symbolic restitu- tion to substitute victims seems appropriate when the immediate casualties can’t be identified or located, or when the injured parties don’t want to accept the wrongdoers’ aid (Harris, 1979). Crea- tive restitution, an ideal solution, comes about when offenders, on their own initiative, go beyond what the law asks of them or their sentences require, exceed other people’s expectations, and leave their victims better off than they were before the crimes took place (Eglash, 1977).

As a legal philosophy, assigning a high priority to restitution means the financial health of victims will no longer be routinely overlooked, neglected, or sacrificed by a system ostensibly set up to deliver “justice for all.” Criminal acts are more than sym- bolic assaults against abstractions like the social order or public safety.” Offenders shouldn’t be prosecuted solely on behalf of the state or the

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people. They don’t only owe a debt to society. They also have incurred a debt to the flesh- and-blood individuals who suffer economic hard- ships because of illegal activity. Fairness demands that individuals who have been harmed be made whole again by being restored to the financial con- dition they were in before the crime occurred (see Abel and Marsh, 1984).

Usually, wrongs can be righted in a straightfor- ward manner. Adolescent graffiti artists scrub off their spray-painted signatures. Burglars repay cash for the goods they have carted away. Embezzlers return stolen funds to the business they looted. Occasion- ally, client-specific punishments are imposed, tailored to fit the crime, the criminal, and unmet community needs. For example, a drunk driver responsible for a hit-and-run collision performs sev- eral months of unpaid labor in a hospital emergency room to see firsthand the consequences of his kind of recklessness. A teenage purse snatcher who preys on the elderly spends his weekends doing volunteer work at a nursing home. A lawyer caught defrauding his clients avoids disbarment by spending time giving legal advice to indigents unable to pay for it. Such sentences anger those who are convinced that imprisonment is the answer and fervently believe, “If you do the crime, you must do the time.” But imaginative dispositions that substitute restitution and community service for confinement are favored by reformers who want to reduce jail and prison overcrowding, cut the tax burden of incarceration, and shield first-time and minor offenders from the corrupting influences of the inmate subculture (“Fitting Justice?,” 1978; “When Judges Make the Punishment Fit the Crime,” 1978; Seligmann and Maor, 1980).

The Rise, Fall, and Rediscovery of Restitution

The practice of making criminals repay their victims is an ancient one. Spontaneous acts of revenge were typical responses by injured parties and their kin before restitution was invented. Prior to the rise of governments, the writing of laws, and the crea- tion of criminal justice systems, the gut reaction of

people who had been harmed was to seek to “get even” with wrongdoers by injuring them physically in counterattacks and by taking back things of value. But as wealth accumulated and primitive societies established rules of conduct, the tradition of retaliatory violence gave way to negotiation and reparation. For the sake of community harmony and stability, compulsory restitution was institution- alized in ancient societies. Reimbursement practices went beyond the simplistic formula of “an eye for an eye and a tooth for a tooth.” Restitution was intended to satisfy a thirst for vengeance as well as to repay losses. These transactions involving goods and money were designed to encourage lasting set- tlements (composition) between the parties that would head off further strife (Schafer, 1970).

In biblical times, Mosaic law demanded that an assailant repay the person he injured for losses due to a serious wound, and required that a captured thief give back five oxen for every one stolen. The Code of Hammurabi granted a victim as much as 30 times the value of any possessions stolen or damaged. Under Roman law, a thief had to pay the victim dou- ble the value of what he stole if he was caught in the act. If he escaped and was caught later, he owed the victim three times as much as he took. And if he used force to carry out the theft, the captured robber had to repay the injured party four times as much as he stole. Under King Alfred of England in the ninth century, each tooth knocked out of a person’s mouth by an aggressor required a different payment, depending upon its location (Peak, 1986).

In colonial America before the Revolution, criminal acts were handled as private conflicts between individuals. Police departments and public prosecutors did not exist yet. A victim in a city could call upon night watchmen for help, but they might not be on duty, or the offender might flee beyond their jurisdiction. If the injured party sought the aid of a sheriff, he had to pay a fee. If the sheriff located the alleged perpetrator, he would charge extra to serve a warrant against the defendant. When the sus- pect was taken into custody, the complainant had to hire a lawyer to draw up an indictment. Then the complainant either prosecuted the case personally or hired an attorney for an additional fee to handle the

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private prosecution. If the accused was found guilty, the person he harmed could gain substantial benefits. Convicted thieves were required to repay their vic- tims three times as much as they had stolen. Thieves who could not hand over such large amounts were compelled to be servants until their debts were paid off. If the victims wished, they could sell these inden- tured servants for a hefty price, and they had one month in which to find a buyer. After that, victims were responsible for the costs of maintaining the offenders behind bars. If they didn’t pay the fees, the convicts were released (Geis, 1977; Jacob, 1977; McDonald, 1977; and Hillenbrand, 1990).

In the years following the American Revolu- tion, the procedures that the British had set up in the colonies were substantially reorganized. Refor- mers were concerned about the built-in injustices afflicting a system in which only wealthy victims could afford to purchase “justice” by posting rewards and hiring sheriffs, private detectives, bounty hunters, and prosecuting attorneys. Crimes were redefined as acts against the state. Settling individual grievances was no longer regarded as the primary function of court proceedings. To pro- mote equal handling and consistency, local govern- ments hired public prosecutors. State agencies built prison systems to house offenders. A distinction developed within the law between crimes and torts. Crimes were offenses against the public and were prosecuted by the state on behalf of “the people.” Torts were the corresponding wrongful acts that harmed specific persons. Criminals were forced to “pay their debt to society” through fines and periods of confinement. But injured parties who wanted offenders to repay them were shunted away from criminal court and directed to civil court, a separate arena where interpersonal conflicts were resolved through lawsuits (McDonald, 1977).

The modern rediscovery of restitution in the United States began in 1967, when the President’s Commission on Law Enforcement and the Admin- istration of Justice recommended the revival of this old practice that had fallen into disuse. Since the 1970s, opinion polls have indicated widespread pub- lic support for its restoration. A greater reliance on restitution also was endorsed by the American Law

Institute, the American Bar Association, the Ameri- can Correctional Association, the National Advisory Commission on Criminal Justice Standards and Goals, the Supreme Court, the National Association of Attorneys General, the Office for Victims of Crime of the Justice Department, and reformist groups such as the National Moratorium on Prison Construction. The Federal Victim/Witness Protec- tion Act of 1982 removed restrictions that had lim- ited restitution to simply a possible condition of probation within the federal judicial system.

Also in 1982, the President’s Task Force on Vic- tims of Crime noted that it was unfair that people suffering serious injuries had to liquidate their assets, mortgage their homes, make do without adequate health care, or cut back on tuition expenses while criminals escaped financial responsibility for the hard- ships they inflicted. The task force recommended that judges routinely impose restitution or else clearly explain their specific reasons for not doing so. The Violent Crime Control and Law Enforcement Act passed by Congress in 1994 made restitution manda- tory in federal cases of sexual assault or domestic vio- lence. The enactment of the Mandatory Victim Restitution Act of 1996 imposed repayment obliga- tions on all violent offenders in the federal system.The Federal Bureau of Prisons created a payment collec- tion program in the late 1980s that many state correc- tional authorities have copied. The growing use of alternative, creative, or constructive sentences reflects the rediscovery of restitution by judges (McDonald, 1988; Leepson, 1982; Harland, 1983; Herrington, 1986; Galaway, 1992; National Victim Center, 1991b; and Office of Justice Programs, 1997).

In the juvenile justice system, restitution has been ordered more often and for a longer period of time. The oldest existing repayment program for people who have been harmed by delinquents was initiated in Florida in 1945. The earliest community service program was set up in South Dakota in 1965. A Min- nesota program established in 1972 was the first to allow youthful offenders to perform direct services for victims instead of paying them in cash. It also pioneered the use of mediation sessions between the two parties to foster a spirit of reconciliation. Hundreds of juvenile restitution projects were set up during the 1970s and

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1980s (Warner andBurke, 1987; Klein, 1997;Roberts, 1998; and Bradshaw and Umbreit, 1998).

Divergent Goals, Clashing Philosophies

Even though support for restoring restitution to its rightful place in the criminal justice process is grow- ing, its advocates do not agree on priorities and pur- poses. Some advocates have been promoting this ancient practice as an additional form of punish- ment, while others tout it as a better method of rehabilitation. Still other champions of restitution emphasize its beneficial impact on the financial well-being of victims and its potential for resolving interpersonal conflicts. As a result, groups with divergent aims and philosophies are all pushing res- titution, but are pulling at established programs from different directions (see Galaway, 1977; Klein, 1997; and Outlaw and Ruback, 1999).

Restitution as a Means of Repaying Victims Those who advance the idea that restitution is primarily a way of helping victims (see Barnett, 1977; and McDonald, 1978) argue that the punitively oriented criminal justice system offers victims few incentives to get involved. Those who report crimes and cooperate with the police and prosecutors incur additional losses of time and money for their trouble (for example, from missing work while appearing in court). They also run the risk of suffering reprisals fromoffenders. In return they get nothing tangible, only the sense that they have discharged their civic duty by assisting in the apprehension, prosecution, and conviction of a dangerous person—a social obligation that goes largely unappreciated. The only satisfaction the system provides is revenge. But when restitution is incorpo- rated into the criminal justice process, cooperation really pays off.

If the primary goal of restitution is to ensure that victims are repaid, then they should be able to directly negotiate arrangements for the amount of money and a payment schedule. Reimbursement should be as comprehensive as possible. The criminal ought to pay back all stolen cash plus the current replacement value of lost or damaged possessions, outstanding medical bills from crime-related injuries

(including psychological wounds attended to by therapists), wages that were not earned because of absence from work (including sick days or vacation time used during recuperation or while cooperating with the investigation and prosecution), plus crime- related miscellaneous expenses (such as the cost of renting a car to replace one that was stolen or the cost of child care when a parent is testifying in court). Repayment on the installment plan should begin as promptly as possible because victims must foot the entire bill in the interim.

Restitution as aMeans of RehabilitatingOffenders Advocates of restitution as a means of rehabilitation (see Prison Research, 1976; and Keve, 1978) argue that instead of being punished, wrongdoers must be sensitized to the disruption and distress that their illegal actions have caused. By learning about their victims’ plights, they come to realize the injurious consequences of their deeds. By expending effort, sacrificing time and convenience, and performing meaningful tasks, they begin to understand their personal responsibilities and social obligations. By making fiscal atonement or doing community ser- vice, they can feel cleared of guilt, morally redeemed, and reaccepted into the fold. Through their hard work to defray their victims’ losses, offenders can develop a sense of accomplishment and self-respect from their legitimate achievements. They may also gain marketable skills, good work habits (such as punctuality), self-discipline, and valuable on-the-job experience as they earn their way back into the community.

If restitution is to be therapeutic, offenders must perceive their obligations as logical, relevant, just, and fair. They must be convinced to voluntarily shoulder the burden of reimbursement because it is in their own best interest as well as being “the right thing to do.” However, offenders probably will define their best interests as minimizing any penalties for their lawbreaking. This includes minimizing pay- ments to injured parties, even if restitution is offered as a substitute for serving time behind bars. Offenders most likely will underestimate the suffering they have inflicted, while those on the receiving end may tend to overestimate their losses and want to

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extract as much as they can (see McKnight, 1981). The sensibilities of wrongdoers must be taken into account, because their willingness to make amends is the key to the success of this “treatment.”

Restitution as a Means of Reconciling Offenders and Their Victims Some advocates of restitution view the process primarily as a vehicle for reconcilia- tion. After offenders have fully repaid the individuals they hurt, hard feelings can dissipate. Also, reconcili- ation between two parties who share responsibility for breaking the law can be achieved after face- to-face negotiations. In situations without a clearly designated wrongdoer, restitution might be mutual, with each of the disputants reimbursing the other for damages inflicted during their period of hostility. Both parties have to consider the restitution agree- ment to be fair and constructive if a lasting, peaceful settlement is to emerge. (The philosophy and oper- ating principles of restorative justice, which relies heavily on restitution, are discussed in Chapter 13.)

Restitution as a Means of Punishing Offenders Those who view restitution primarily as an addi- tional penalty (see Schafer, 1977; and Tittle, 1978) argue that for too long offenders have been able to shirk this financial obligation to their victims. First, convicts should suffer incarceration to pay their debt to society. Next, they should undertake strenuous efforts to repay the specific individuals they harmed. Only then can their entanglement with the criminal justice system come to an end.

Reformers who promote restitution as a means of repaying victims, as a way of rehabilitating offen- ders, or as the basis for bringing about mutual recon- ciliation can come into conflict with crime control advocates who view restitution as an additional means of punishment and deterrence. The problem with imposing restitution as an extra penalty follow- ing incarceration is that it delays repayment for many years. Because few convicts can earn decent wages while behind prison walls, the slow process of re- imbursement cannot begin until their period of confinement is over, either when the sentence expires or upon the granting of parole. When punishment takes priority over reimbursement, the

victims’ financial needs, the offenders’ therapeutic needs, and the community’s need for harmony are subordinated to the punitive interests of the state. As long as prison labor remains poorly paid, restitution and incarceration will be incompatible.

The major argument against the centrality of victim reimbursement is that the operations of the criminal justice system are intended to benefit soci- ety as a whole, and not just the injured party. Other considerations should come first: punishing crim- inals harshly to teach them a lesson and to deter would-be lawbreakers from following their exam- ple; treating offenders in residential programs so that they can be released back as rehabilitated and productive members of the community; or incapac- itating dangerous persons by confining them for long periods of time. Subordinating these other sentencing objectives to restitution would reduce the legal system to a mere debt collection agency catering to victims, according to a 1986 Supreme Court decision (Triebwasser, 1986).

Opportunities to Make Restitution

Restitution is an extremely flexible sanction that is not being used to its full potential. It can be applied at each stage in the criminal justice process, from the immediate aftermath of the crime up until the final moments of parole supervision following a period of imprisonment. Figure 12.1 illustrates how restitution can be an option at every decision-making juncture.

As soon as a suspect is apprehended, an informal restitution arrangement can settle the matter. For example, a storekeeper might order a shoplifter to put the stolen item back on the shelf and never return to the premises, or parents might offer to pay for their son’s spray painting of a neighbor’s fence. In most states, however, serious offenses cannot be resolved informally. It is a felony for a victim to demand or accept any payment as “hush money” to cover up a major violation of the law, in return for not pressing charges, or as a motive for discontinuing cooperation with the authorities in an investigation or prosecu- tion. A criminal act is an offense against the state in addition to a particular person and cannot be settled privately (Laster, 1970).

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After a suspect is arrested, a restitution agree- ment can be worked out as an alternative to prose- cution (diversion). If a defendant is indicted, the district attorney’s office can make restitution a con- dition for dismissing formal criminal charges. Once prosecution is initiated, restitution can be part of a plea bargain struck by the defense lawyer and the district attorney, wherein the accused concedes guilt in return for lesser penalties. Restitution is particularly appropriate as a condition of probation or of a suspended sentence. If incarcerated, an inmate can try to begin to repay the injured party from the meager wages he earns from labor in prison, but he will be more capable of putting money aside if he gets a real job while he is on work release or when he resides at a halfway house. After serving time, restitution can be included as a condition of parole. Restitution con- tracts can be administered and supervised by various

parties concerned about the crime problem: com- munity groups, private and nonprofit charitable and religious organizations, juvenile courts, adult crimi- nal courts, probation departments, corrections departments, and parole boards.

Yet as promising as restitution seems to be, it is not the answer formost victims. Only a small percent- age will ever collect anything. The problem is directly parallel to the quest for emotional satisfaction from retribution. Just as most criminals escape punishment, most also evade restitution. The phenomenon of case attrition has been labeled funneling, or shrinkage, and has been likened to a “leaky net.” At the outset, many cases seem appropriate for restitution. But at the end of the criminal justice process, only a relative handful of injured parties receive even partial restitu- tion. All the other cases (and offenders) have slipped through holes in the net. Figure 12.2 explains how and why so many “escape” their financial obligations.

Crimes committed

Crimes not reported by victims to the authorities

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Criminals not indicted

Criminals not prosecuted

Criminals not convicted

Criminals not able to make restitution

Criminals not willing to make restitution

Victims not willing to accept restitution

Criminals who don’t repay their victims

Criminals who repay their victims

F I G U R E 12.2 Case Attrition, Funneling, or Shrinkage: The Leaky Net

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First of all, a large number of offenders will never have to make amends because their victims do not report the incidents to the police (refer back to Table 6.1). Next, the majority of offenders get away with their crimes because the police cannot figure out who the perpetrators are (clearance rates are especially low for the most numerous property crimes: burglaries, car thefts, and other forms of stealing; see Table 6.3). Hence, right away most of the people who have suffered harm already have been eliminated from any chance of receiving reimbursement. For example, only about one-half of all robberies are reported, and only one-quarter are solved, so only one out of eight robbery cases enters the system.

Of the relatively small number of crimes that are solved by an arrest, additional problems can arise dur- ing the adjudication process. The overwhelming majority of cases (upwards of 90 percent in many jur- isdictions) are resolved through plea negotiations that involve dropping charges or counts. Many complai- nants are eliminated from consideration if offenders do not admit to hurting them. Some cases that go to trial result in acquittals, and some convictions are reversed on appeal. Of those who are convicted or who plead guilty,many are unwilling or unable to shoulder finan- cial obligations. Judgesmay not order convicts to repay the people they harmed. Inmates usually cannot earn substantial amounts of money. Prisoners granted parole have trouble finding any work, let alone a job that pays enough to allow them to set asidemeaningful amounts after all their other deductions.

Finally, many jurisdictions lack both a tradition of ordering restitution and a mechanism for moni- toring and enforcing such arrangements. Actually collecting the funds in a timely manner remains a major challenge for victims (Harland, 1983; McGillis, 1986; and Davis and Bannister, 1995).

Obstacles Undermining Restitution

Economic realities limit the ability of many convicts to meet their restitution obligations. Because the street crime problem is in large part an outgrowth of poverty and the desperation it breeds, restitution obligations collide with competing claims for the

same earnings. Ex-offenders have more pressing expenses and other debts. Furthermore, restitution is predicated on work that pays a living wage. Offenders must have, must be helped to find, or must be given reasonably well-paying jobs. These jobs need to pay far more than the minimum wage to permit installments for victims to be deducted from total after-tax earnings. But the U.S. economy cannot provide decent jobs for all who want to earn a living, even during the best of times.

Many dilemmas arise when restitution obliga- tions are considered within the context of intense competition for the limited number of well-paying jobs convicts are capable of doing. If a position is found or created for an ex-offender, then the pro- spects for the successful completion of the restitu- tion obligation are increased. Otherwise, the victims of down-and-out street criminals are denied a real chance to get repaid. If the job pays low wages, then the repayment process cannot be com- pleted within a reasonable amount of time. If nearly all of the ex-offender’s earnings are confiscated and handed over to the victim, that would jeopardize the wrongdoer’s commitment to the job and to repaying the debt. If the job is demeaning, then its therapeutic value as a first step in the direction of a new lifestyle built on productive employment is lost. If the job is temporary and only lasts for the duration of the restitution obligation, then the risk of returning to a career of crime is heightened.

But if a job found or created for an ex-offender is permanent and pays well, then some observers might object that criminals are being rewarded, not punished, for their misdeeds. Law-abiding peo- ple desperately seeking decent jobs will resent any policy that seems to put offenders at the front of the line. Trade union members rightfully will fear that convict labor could replace civilian labor over the long run. But if inmates are put to work in large- scale prison industries, then business interests and labor unions justifiably will complain about unfair competition. If adolescents owing restitution are too young to receive working papers, then a job in private industry would violate child labor laws. Only unpaid community service would be permissible—but then victims get nothing.

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When the injured parties are hard-pressed to make ends meet, restitution seems appropriate and fair. But if indigent offenders must hand over money to affluent victims, then restitution smacks of exploitation—taking from the poor and giving to the rich. Conversely, if prosperous offenders (such as white-collar criminals) are allowed to pay off their obligations from their bank accounts and not with hard work, it will appear that they are buying their way out of trouble. If poor people are kept behind bars and denied the opportunity to make restitution as a condition of probation or parole because they lack marketable job skills, such discrimination against an entire class of people seems to be a violation of the equal protection clause of the Fourteenth Amendment.

Yet in jurisdictions where the criterion for release from confinement was a perceived ability to repay, a typical participant in a restitution program turned out to be a white, middle-class, first-time property offender, and the most common recipient of reimbursement was a business, studies showed (see Galaway and Hudson, 1975; Edelhertz, 1977; Hudson and Chesney, 1978; Gottesman and Mountz, 1979; Harland, 1979, 1981a; and Outlaw and Ruback, 1999).

Restitution in Action

Courts in every state now have the authority to order restitution. Victims are promised a right to restitution in some states that have adopted pro- victim constitutional amendments. In many states,

judges are supposed to impose restitution obliga- tions on convicts whenever possible and if appro- priate, unless there are compelling or extraordinary circumstances (which must be entered into the record in writing). Restitution should routinely be part of the sentence after either negotiated pleas or trials. Often, judges are specifically directed to order reimbursement in cases of child abuse, elder abuse, domestic violence, sexual assault, identity theft, drunk driving, and hate crimes. The repayment can cover outlays for medical expenses, counseling bills, replacing property that was damaged or destroyed, lost wages, other direct costs, and even funeral expenses (National Center for Victims of Crime, 2002d).

Statistics compiled by the federal government shed light on the actual rate of ordering convicts to make restitution in state courts around the country. The national data compiled in Table 12.1 reveals that, in general, judges have not been imposing restitution obligations on most offenders. Judges ordered felons to repay their victims in addition to another sentence (usually a term of incarceration, but sometimes a fine or compulsory treatment) in only a fraction of all convictions for either violent crimes or property crimes. Restitution was part of the sentence in a larger percentage of felony con- victions for burglary, larceny, motor vehicle theft, and fraud than it was for murder, rape and other sexual assaults, robbery, and aggravated assault. Peo- ple who commit fraud are the most likely to have to pay back their victims (who might be businesses rather than individuals). Murderers are the least

T A B L E 12.1 Percentages of Convicted Felons Sentenced to Restitution as an Additional Penalty in the 75 Largest Jurisdictions Nationwide, Selected Years, 1996–2006

1996 1998 2000 2002 2004 2006

Convicted for: Murder 9 10 11 7 14 13 Rape and sexual assault 9 11 11 10 16 18 Robbery 11 13 13 10 16 18 Aggravated assault 14 14 13 11 15 18 Burglary 21 23 24 20 24 27 Larceny 22 21 25 19 26 26 Vehicle theft 22 21 27 19 37 28 Fraud 32 29 31 24 30 29

SOURCES: BJS, 2008c; and Rosenmerkel et al., 2010.

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likely of all felons to be forced to take financial responsibility for the losses they inflicted (presum- ably to the families of the people they killed).

As for changes over time, the imposition of restitution by judges may have been creeping upward during the late 1990s but slipped backward during 2002. However, by 2006, the ordering of repayment in state courts rebounded and reached new highs that surely were still disappointingly low to those who firmly believe in restitution as an important component of criminal justice. The trends in Table 12.1 were derived from a court monitoring system operated by the Department of Justice that tracks dispositions in nearly one million cases every two years in the nation’s 75 largest jur- isdictions (see Langan and Graziadei, 1995; Durose, 2004; BJS, 2008c; and Rosenmerkel et al., 2010).

Another set of figures from this federal database is worth examining for national trends (see Table 12.2). In theory, making restitution is more feasible if a con- vict is on probation rather than behind bars. In prac- tice, restitution doesn’t materialize most of the time. Of felons whowere fortunate enough to be sentenced to probation for violent acts, only about 1 in 7 was ordered by a judge in state court to try to reimburse those they harmed as one of the conditions they must obey; and in 2006 this fraction plunged to merely 1 in 11. Felons on probation for property crimes make restitution at a higher rate. But the direction of drift once again seems downward, from two-fifths of all probationers working off their debt in 1996 down to only roughly one-fourth in 2006. This backward trend over more than 20 years toward disuse in both violent and property crimes (seemingly the easiest and most appropriate cases), rather than forward toward greater use, is another disappointment to people who believe in the appropriateness of restitution.

The three most frequently cited reasons for judges failing to impose restitution all fault victims: they didn’t request reimbursement, they failed to document their losses, or they were unable to cal- culate their exact expenses. Often, judges felt that restitution obligations would be inappropriate if convicts also had to “repay society” by serving time behind bars or if they had a very limited potential to earn a living wage.

Despite these obstacles, limitations, conflicting priorities, dilemmas, and ironies, restitution is under way in many jurisdictions. Probation departments run most supervision and collection programs (75 percent) (Office of Juvenile Justice and Delin- quency Prevention, 1998b).

When criminologists and victimologists evaluate the effectiveness of these programs, the challenge is to identify the specific goals and to devise appropriate criteria to measure degrees of success and failure. Victim-oriented goals involve making the injured parties whole again by enabling them to collect full reimbursement and to regain peace of mind (recovery from emotional stress and trauma). Offender-oriented goals are achieving rehabilitation and avoiding recidivism. System-oriented goals include reducing case processing costs, relieving tax- payers of the financial burden of compensating peo- ple who have been harmed, alleviating jail and prison overcrowding through alternative sentences, and improving citizen cooperation by providing material incentives to injured parties for participating in the criminal justice process. So many different aims and touted benefits coexist that no sweeping conclusions can be drawn about the effectiveness of the programs now in operation (for example, see McGillis, 1986; Butts and Snyder, 1992; Jacobs and Moore, 1994; and Davis, Smith, and Hillenbrand, 1992).

T A B L E 12.2 Percentage of Convicted Felons Placed on Probation Who Have Restitution Obligations in the 75 Largest Jurisdictions Nationwide, Selected Years, 1994–2006

1994 1996 2000 2002 2004 2006

On Probation for: Violent crimes 15 15 14 15 15 9 Property crimes 34 40 33 32 26 24

SOURCES: Reaves, 1998; Hart and Reaves, 1999; Rainville and Reaves, 2003; Cohen and Reaves, 2006; Kycklehahn and Cohen, 2008; and Cohen and Kycklehahn, 2010.

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To improve the chances that convicts will make at least partial restitution, notification laws could be strengthened to ensure that victims are advised of their rights. Prosecutors could bear the routine responsibility of requesting restitution, or restitution could be considered mandatory unless the judge specifically excuses the offender from this obligation. Pre-sentence investigation reports and victim impact statements could be used as a stan- dard form to document claims for repayment (NCVC, 2002c). To better enforce restitution orders, judges could routinely investigate the assets of convicts before crafting a workable payment plan. To decrease the likelihood of default, prosecutors could obtain injunctions to prevent defendants from hiding or quickly spending their assets (cash, savings, investments, homes, vehicles, valuable possessions), and probation and parole departments could more closely monitor these court-ordered payments, and either revoke or extend periods of probation and parole if the convict willfully refuses to make timely payments. The money to be handed over can be deducted from inmates’ wages from prison labor, state and federal income tax refunds, lottery winnings, inheritances, trust accounts, and collateral used for bail. If convicts default, private collection agencies can be called, and unpaid bal- ances can be converted into civil judgments enforced by seizures of property by sheriffs’ departments (NCVC, 2002b).

However, for those who become impatient and dissatisfied with criminal-court-ordered restitu- tion, another avenue for reimbursement can be pursued: lawsuits in civil court.

WINNING JUDGMENTS IN CIVIL COURT

The Revival of Interest in Civil Lawsuits

A famous retired football player is put on trial for the murder of his ex-wife and her friend, but he is acquitted by a jury that is not convinced of his guilt beyond a reasonable doubt by the prosecution’s extensive but extremely complicated

forensic evidence. The outraged families of the murder victims sue him in civil court. A jury finds him liable for the wrongful deaths and awards the two families more than $33 million in compensatory and punitive damages. When he announces that he is writing a book entitled “If I Did It, Here’s How It Happened,” the two families are divided over whether to go after the royalties to speed up the slow payment of the judgment. Thirteen years to the day after he was acquitted of murdering his former wife, he is convicted of taking part in an armed robbery of sports memorabilia by a group of men in a hotel room and is sentenced to prison. He appeals the conviction, arguing that his attorneys were improperly barred from asking prospective jurors about their knowledge of his previous acquittal in criminal court and the subsequent judgment against him in civil court, but his lengthy sentence is upheld. (Ayres, 1997; and Martinez, 2010)

■ ■ ■

The wife of a well-known television and movie star is shot while she sits in their car outside of a restaurant. He is put on trial but acquitted. The district attorney angrily brands him, “guilty as sin” and denounces the jury as “incredibly stupid.” The wife’s four grown children decide to sue the actor in civil court, contending that either he killed her himself or hired someone to do it. Although he did not testify at his murder trial, he is compelled to take the stand and answer questions in civil court. Ten of the twelve jurors conclude that he was involved in the slaying, and the judge orders him to pay $30 million to his dead wife’s four children. He declares bankruptcy and appeals the judgment. Several years later, a judge halves the damages he owes her children but rules that the jury did not act improperly when it discussed “sending a message” to celebrities that they can’t get away with murder or molestation, as they may have in other cases. (Associated Press, 2005; BBC, 2008; and Morrison, 2010)

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A growing number of victims are no longer content to just let prosecutors handle their cases in criminal court, especially if convictions are not secured. They have discovered that they can go after their alleged wrongdoers and pursue their best interests in a different arena: via a lawsuit in civil court.

Criminal proceedings are intended to redress public wrongs that threaten society as a whole. As a result, the economic interests of injured parties seeking restitution from convicts routinely are sub- ordinated to the government’s priorities, whether probation, incarceration, or execution. Injured parties seeking financial redress are directed to civil court. There they can launch lawsuits designed to remedy torts—private wrongs—arising from violations of criminal law. Under tort law, plaintiffs (victims) can sue defendants and win judgments for punitive damages (money extracted to punish wrongdoers and deter others) as well as compensatory damages (to repay expenses).

Activists in the victims’ movement like to call attention to these often-overlooked legal rights and opportunities. Guilty verdicts in criminal courts cost offenders their freedom; successful judgments in civil courts cost offenders their money. Lawsuits can be successful even if charges are not pressed or if the alleged perpetrator is found not guilty after a trial in criminal court. Centers for legal advo- cacy and technical assistance have sprung up in many cities to make lawsuits an occupational hazard and a deterrent for habitual criminals (Barbash, 1979; Carrington, 1986; Carson, 1986; and National Victim Center, 1993).

The Litigation Process

Civil suits can involve claims for punitive damages as well as compensatory and pecuniary damages. Awards for compensatory damages (repayment of expenses) and pecuniary damages (to cover lost income) are supposed to restore victims to their for- mer financial condition (make them “whole” again). They can receive the monetary equivalent of stolen or vandalized property, wages from missed work, projected future earnings that won’t materialize

because of injuries inflicted by the offender, and out- lays for medical and psychiatric care (hospital bills, counseling expenses) plus recompense for physical pain and mental suffering (resulting from loss of enjoyment, fright, nervousness, grief, humiliation, and disfigurement). Punitive damages might be lev- ied by the court to make negative examples of law- breakers who deliberately act maliciously, oppressively, and recklessly (Stark and Goldstein, 1985; and Brien, 1992).

In civil courts, victims and their kin can sue offenders for certain intentional torts. Wrongful death suits enable survivors to collect compensa- tion for the loss of a loved one without justification or legitimate excuse and for assault, which covers acts sufficiently threatening to cause fear of imme- diate bodily harm. Suits for battery involve inten- tional, harmful, physical contact that is painful, injurious, or offensive. Suits charging trespass cen- ter upon the intentional invasion of another per- son’s land. Conversion of chattel suits accuse defendants of knowingly stealing or destroying the plaintiffs’ possessions or property through theft or embezzlement. Suits alleging false imprisonment contend that the offender held the plaintiff against his or her will, even if for a brief period of time, such as during a hostage taking or rape. Charges of fraud can arise from white-collar crimes if inten- tional misrepresentation and deception can be established. Finally, suits can allege that the defen- dant intentionally or recklessly inflicted emotional distress through extreme or outrageous conduct, such as by stalking the plaintiff (Stark and Goldstein, 1985; Brien, 1992; and National Crime Victims Bar Association, 2007).

Civil actions commence when the plaintiff (also called the second party) formally files a com- plaint (also referred to as a pleading). This docu- ment includes a brief statement of the legal jurisdictional issues, a summary of the relevant facts of the case (the causes of action that show how the harm to the victim was a “direct and prox- imate result” of the alleged wrongdoer’s behavior), and a request for relief for the injuries and damages sustained (monetary compensation). The victim’s attorney brings the complaint to civil court and

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pays a fee. A deputy sheriff (or a privately retained process server) must physically hand this written document to the defendant (also called the first party), along with a summons requiring a response to the allegations within a stated period of time (usually one month). The accused wrongdoer sub- mits an answer either admitting to the charges or, more likely, contesting them and issuing a defense (or perhaps even launching a countersuit).

In preparing for a trial to resolve the competing claims, both parties engage in a process called dis- covery, in which they exchange written replies to questions, documents, and sworn statements of eye- witnesses (including police officers). Just as in crim- inal proceedings, the typical outcome is a negotiated compromise agreement. But if an out- of-court settlement cannot be reached, the accused exercises his Seventh Amendment right to a trial, and the injured party has to prove the allegations in court. After considerable delays because of con- gested court calendars, the trial is held before twelve (or, in some states, six) jurors or perhaps only in front of a judge (Stark and Goldstein, 1985).

In civil proceedings, the defendant in third- party lawsuits is likely to allege contributory negli- gence (the injured party was partly responsible for what happened). In battery cases, the rebuttal might be victim provocation (leading to responses neces- sary for self-protection). In other lawsuits, the defense might argue that the plaintiff knowingly and voluntarily “assumed the risk”; for example, a woman alleging rape was drinking heavily and agreed to go to the man’s apartment (Stark and Goldstein, 1985; and National Crime Victims Bar Association, 2007).

Following opening statements presented by attorneys for each side, witnesses testify and are cross-examined, and physical evidence is intro- duced. Interrogatories (lists of questions for the other side to answer), depositions (answers to the opposing lawyer’s questions), and requests for documents may generate important evidence. Then each party’s attorney sums up, and the jury retires to deliberate. The jury votes and then ren- ders its verdict on which of the two versions of

events seems more truthful. The jury awards com- pensatory and perhaps punitive damages if it finds for the plaintiff and rejects the defendant’s argu- ments. The losing party is likely to appeal the deci- sion, and a higher court can overturn the trial court’s verdict if errors in procedural law are dis- covered or if the jury acted contrary to the evi- dence. Appeals may take many years to be resolved (Stark and Goldstein, 1985).

Litigation in civil court usually follows rather than precedes adjudication in criminal court. Peo- ple who have been badly hurt usually wait to pro- ceed with litigation because the evidence that is introduced during the criminal proceedings can be used again in the lawsuit and generally is sufficient to establish that a tort occurred. Furthermore, if the civil action is filed too early, the defense attorney will use this fact to try to undermine the complai- nant’s credibility as a witness for the prosecution, claiming that the testimony is motivated by poten- tial financial gain. But if the civil action is not filed for years, the statute of limitations might run out, and it will be too late to sue the defendant. For example, in most states, lawsuits alleging assault must be filed within two years, before complai- nants’ and defendants’ memories fade and material evidence is lost or destroyed (Brien, 1992).

Possibilities and Pitfalls Injured parties who are considering civil litigation must weigh the advan- tages and disadvantages of this course of action. One reason civil lawsuits are relatively uncommon is that most victims conclude that the benefits are not worth the costs. In addition, many people are unfamiliar with this option.

Civil lawsuits have several attractions. First and foremost, victims can seize the initiative, haul their assailants into court, bring them to the bar of jus- tice, and sue them for all they can get. In criminal cases, prosecutors exercise considerable discretion and make all the important decisions, even in jur- isdictions where victims have the right to be informed and consulted. In civil cases, victims can regain a sense of control and feel empowered. They are principal figures entitled to their day in court, are aware of all the facts surrounding the case, and

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can’t be excluded from the courtroom. It is up to them to decide whether to sue and whether to accept a defendant’s offer of an out-of-court settle- ment. (In small-claims courts, plaintiffs don’t even need an attorney. They can present their own cases using simplified procedures designed to expedite trials, because not much money is at stake).

Plaintiffs seeking large awards must hire attor- neys of their own choosing and can participate in developing a strategy and preparing the case in anticipation of the trial. Victims can achieve full reimbursement, perhaps even more money than they lost, through lawsuits. They can collect punitive damages far in excess of actual out- of-pocket expenses, and can receive compensation for the mental pain and emotional suffering they endured. Defendants’ assets, including homes, cars, savings accounts, investments, and inheritances, can be attached (confiscated), and their wages can be garnished. Most attorneys practicing civil law accept cases on a contingency basis and don’t charge a fee unless they win. Suits can be brought by the victims’ family (parents, children, spouse, or sib- lings) if an injured party is too young, mentally incapacitated, or dies (Stark and Goldstein, 1985; Brien, 1992; and National Crime Victims Bar Association, 2007).