1Forensic Science and Criminalistics

Associated Press

Learning Objectives After reading this chapter, you should be able to do the following:

▪ Define forensic science and how it contributes to a case, as well as explain the CSI Effect and the scientific method.

▪ Summarize the history of forensic science and contributors to the field.

▪ List and describe some forensic science specialties.

▪ Identify the elements of a forensic investigation, how physical evidence can be produced, and forensic analysis.

▪ Describe the work and work product of a forensic scientist.

▪ Describe the U.S. court system, and the key rulings on physical evidence admissibility through expert testimony.

▪ List and discuss major issues in forensic science today.

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5Forensic Toxicology

Jochen Tack/imageBROKER/SuperStock

Learning Outcomes After reading this chapter, you should be able to

▪ Describe the types of cases that toxicologists analyze.

▪ Identify different poisons and how they are sampled.

▪ Explain how officers recognize drugs and alcohol in the field and how they obtain samples for the toxicologist.

▪ Discuss how toxicologists test blood and urine samples for drugs and alcohol.

▪ Describe the drugs used in drug-facilitated sexual assault and how they are analyzed.

▪ Explain the purposes of forensic urine drug testing and how it is done.

© 2019 Bridgepoint Education, Inc. All rights reserved. Not for resale or redistribution.

Section 5.1Toxicology Cases

Introduction Poisons have been present throughout human history. Poisoning can be accidental. For instance, someone can eat the wrong plant, mushroom, or fish and die. However, poison- ings can also be planned. Poisons derived from plant extracts have been used in executions; Socrates suffered this fate. He was found guilty of crimes against the state and was given a cup of hemlock to drink. In the past, if you wanted to kill an enemy, there were preparations available that could complete the task. Today poisons are not used as often as instruments of homicide. However, methods of analysis have been found that can determine the presence of toxins in the body and can assist the courts in determining if a person was indeed poisoned or under the influence of a toxin or intoxicating compound.

In today’s world, we come in contact with tens of thousands of chemicals. Many are not harm- ful, but there are many others that are. We discussed drugs in Chapter 4, so we are aware that drugs can cause death if taken in overdose quantities. In fact, nearly every drug can be fatal if enough is consumed. Essentially, this makes almost every drug a poison. Even consumption of excessive water can deplete essential electrolytes in the body and cause death.

An interesting point can be derived from this knowledge: It is the dose that makes a poison. This means that if taken in small enough amounts, some poisons can be used as drugs. This has been the case for many years. For example, arsenic was previously used to control rats and other vermin populations, but it was also used at one time in some Chinese homeopathic medicines in very low doses. Anticancer drugs are poisons that are designed to kill many can- cer cells while killing relatively few healthy cells. Toxicology, therefore, is the study of drugs and poisons or toxins and the way they affect the body. It comprises knowledge from two dis- ciplines—pharmacodynamics, which studies the way drugs act on the body in both positive and negative ways, and pharmacokinetics, which studies how the body acts on drugs. These disciplines and the information gained from the analysis of samples taken during investiga- tions by law enforcement can be used in court cases to help the trier of fact come to a conclu- sion about that case. This science is known as forensic toxicology.

5.1 Toxicology Cases Forensic toxicologists always have a monumental task before them in finding toxic substances and poisons in the body, quantitating the level in the system, and determining possible effects, such as the increasing amount of impairment as individuals consume more alcohol and raise their blood alcohol concentration (BAC). The toxicologist will usually engage in analysis of two types of cases. The first type involves poisonings, both accidental and intentional. The second type involves people who use illicit drugs in a recreational manner or victims who have been given drugs without their knowledge. Those involve issues in which humans are under the influence of one or more compounds that impair their ability to perform tasks (human performance cases). Such cases are typical for the forensic toxicologist and involve driv- ing under the influence of alcohol (DUI) or driving under the influence of drugs (DUID). The toxicologist performs analyses that can find many more compounds than the drug chemist. A toxicologist also searches for compounds in blood, urine, or other biological samples, where the concentration of compound present is in the parts per million range, and the interfering components in the sample can be in the hundreds. In comparison, a drug chemist looks for a drug in a tablet, capsule, powder, or plant material, where the amount of drug is determined

© 2019 Bridgepoint Education, Inc. All rights reserved. Not for resale or redistribution.

Section 5.2Poisons

as a percentage of the total weight of the sample, and there are relatively few interfering compounds or diluents. Another factor in a toxicologist’s work is metabolism. Metabolism is the body’s way of breaking down a poison or drug into compounds called metabolites. Metabolites are compounds that can be eliminated from the body more efficiently than the parent compound (the poison or drug). In order to facilitate elimination, drugs are usually made more water soluble so they can be deposited in the urine. Once in the urine, they can be eliminated from the body. There are other ways to get rid of a drug, but transforming it into a metabolite for removal is the most common. If metabolism has progressed far enough, the original drug or toxin will not be found in the body. Instead, the analyst must search for one or more metabolites of the drug. As we will see, all of these factors make forensic toxicology a very interesting job.

The majority of cases submitted for forensic toxicological analysis will include two classes of compounds. Those classes are (a) drugs of both the licit and illicit kind and (b) volatile sub- stances, such as ethanol and inhalants. Other toxins may be encountered, but to a much lesser extent. These include gases, metals, pesticides, and other miscellaneous compounds. Cases and samples involving all of these compounds will make their way to a forensic toxicology laboratory from a coroner’s office or medical examiner’s office and through law enforcement personnel.

There are also privately run laboratories that perform forensic toxicology testing in support of drug-use prohibitions, such as in certain occupations or in athletic competitions. This aspect is discussed later in the chapter.

5.2 Poisons Historical poisons are encountered by the forensic toxicologist on a limited basis, but there are several types of poisons. Most will likely be seen in general circumstances. Heavy metals, such as arsenic, mercury, and lead, are often encountered by people because of accidental ingestion. There have been cases of homeowners removing lead-based paint with hair dry- ers without adequate ventilation; these people have come down with lead poisoning from inhaling the fumes generated by the heat of the hair dryer. Children have succumbed to lead poisoning from eating chips of lead-based paint. Family members and their pets have experi- enced arsenic poisoning after contact with older rat poisons. Other metals, such as thallium, cadmium, cobalt, and selenium, are included in this class, though they are not often encoun- tered or easily obtained and would most likely be involved in a case of intentional poisoning.

In these cases, blood and urine samples can be tested by the toxicologist. The principal test utilized is atomic absorption spectroscopy (AA), which is sensitive to the µg/L level. Scientists

Think About It

While many forensic toxicology cases involve DUI and DUID—and these seem like pretty straightforward trials—forensic toxicologists spend a great deal of time in court on these cases. Why do you think they are called to court so often?

© 2019 Bridgepoint Education, Inc. All rights reserved. Not for resale or redistribution.

Section 5.2Poisons

measure everything in metric system units: “µ” means micro, or one millionth; “g” stands for grams. There are about 28 grams in an ounce. “L” means liter, which is around a quart.

New testing methods have made it possible for other samples to be tested. Hair testing for some of the heavy metals, though not lead, can allow the toxicologist to determine whether the dosing was acute, or one time only, or happened over a period of time, called chronic dos- ing. Analysis of tissue samples postmortem would also be completed using AA, and it could be used to quantitate the level in the body to determine if it was metal poisoning that killed the victim.

Cases involving toxic substances have also been seen. For instance, in the early 2000s, ethyl- ene glycol, a substance once commonly found in radiator fluid, was responsible for a large number of poisonings, some accidental and some not. The Georgia Poison Control Center, for instance, had 235 cases in 2004 (Morgan, Geller, & Kazzi, 2011). The ethylene glycol is metab- olized in the body to form a toxic substance that can be lethal. The ethylene glycol has been replaced in most of these fluids with propylene glycol to try and eliminate this type of poison- ing, or in some cases a very bitter flavoring has been added to prevent accidental ingestion. As of 2012 all producers of antifreeze for automobile use have either switched to propylene gly- col or added the bitter flavoring agent. Interestingly, there have been three recent murder mysteries in which the killer used ethylene glycol in radiator fluid as the poison of choice.

Recall from Chapter 1 that Mathieu Joseph Bonaventure Orfila is often called the father of forensic toxicology. In 1840 Dr. Orfila became involved in one of the most famous (or infa- mous) cases of murder by poisoning in history, in which Marie Lafarge was convicted of poi- soning her husband, Charles, with arsenic.

Think About It

There is a wealth of knowledge communicated through the media and Internet, including information on the use of poisons. Do you feel that placing information of this nature on television and the Internet allows people too much access to informa- tion that can prove to be harmful to people?

Case Illustration: Toxicology and Murder—in the Beginning: The Lafarges

Marie married Charles Lafarge in 1839. Although she did not come from an aristocratic background, she had been sent to the best schools and had moved in the best circles. She agreed to marry Charles under the mistaken impression that he owned property and had a successful business. In fact, he was marrying Marie for her dowry, to help pay down his debts.

They moved to a run-down house owned by Charles. She was quickly disillusioned about this arrangement and encouraged Charles to go to Paris to try to raise money. While he

(continued on next page)

Case Illustration: Toxicology and Murder—in the Beginning: The Lafarges (continued)

was away in Paris, Marie sent him a Christmas cake. After eating a piece of it, he became violently ill. He discarded the remainder of the cake, but did not think about seeing a doc- tor; he thought the cake had spoiled in transit. He still did not feel well after returning home. Marie prepared his meals during this time, and he again fell ill. The family doctor thought the symptoms were “cholera-like” and was not suspicious when Marie asked him for a prescription for arsenic to kill the rats that were disturbing Charles at night. Charles’s health deteriorated rapidly, and he eventually died. His family, and others who had come to keep watch and help him, became suspicious of Marie. She had been observed stirring a white powder into food and drink intended for Charles. A doctor that was consulted close to the time Charles died began to suspect poisoning, but it was too late.

One of Charles’s brothers, whose suspicions had been aroused, contacted the local police, and a magistrate came to do an inquiry. He took possession of some food items that remained, which could contain a poison. He learned that Marie had purchased arsenic not long before Charles had received the cake in Paris and again after he returned home. Marie’s gardener confirmed that she had given him arsenic to make a paste to kill rats. This paste was found around the house, but it did not appear to have been disturbed by rats. The magistrate also asked Charles’s local doctors if they could perform a new test for arsenic that he had heard about: the Marsh test. The doctors agreed but did not know about the test’s intricacies. They used older methods to test Charles’s stomach contents taken at autopsy and obtained inconclusive results. Nevertheless, they reported arsenic present. One of the people tending to Charles had taken Marie’s box, from which people had seen her taking the white powder for Charles’s food and drink, and it was turned over to the magis- trate. Arsenic was found in the box. In addition, the arsenic paste that had been placed in the house for the rat problem was found to be a mixture of flour, water, and baking soda.

Marie was put on trial for murder. One of Marie’s lawyers knew Dr. Orfila. He submitted the local doctors’ arsenic testing results to Orfila and asked for an opinion. Orfila submitted an affidavit to the trial court stating that the tests had been conducted poorly and that the result meant nothing. When the local doctors testified about the arsenic in Charles’s body, the lawyer read Orfila’s affidavit informing the court about the Marsh test and insisted that he be called to do the test and as a witness. Prosecutors were confident of Marie’s guilt and said they would agree to the testing, but they did not see the necessity of calling Orfila (who was the acknowledged expert on the Marsh test in Europe at the time). The judge agreed and ordered that local pharmacists conduct the testing. They reported not finding any arsenic in the stomach contents taken at autopsy. Charles’s body was then exhumed and new specimens taken. The pharmacists again failed to find arsenic. Marie seemed to be vindicated.

However, the prosecutor learned from Orfila’s writings that arsenic can leave the stom- ach through normal digestive processes and thus not be present in the contents. He also remembered the saved food items that Marie had given to Charles. He asked that they be tested. The defense, now confident about their case, agreed. This time, though, the pharma- cists came back and said there was a large amount of arsenic in the food items. The pros- ecutor again asked the judge to permit Orfila to come in and settle the matter, since there had been contradictory results. The defense more or less had to agree to this, having con- sulted Orfila first. Orfila conducted his tests in the presence of the pharmacists and found that arsenic was present in specimens taken from Charles’s body. The defense team sought to call an opposing expert, François Raspail, who had opposed Orfila in court at other

(continued on next page)

© 2019 Bridgepoint Education, Inc. All rights reserved. Not for resale or redistribution.

Section 5.2Poisons

measure everything in metric system units: “µ” means micro, or one millionth; “g” stands for grams. There are about 28 grams in an ounce. “L” means liter, which is around a quart.

New testing methods have made it possible for other samples to be tested. Hair testing for some of the heavy metals, though not lead, can allow the toxicologist to determine whether the dosing was acute, or one time only, or happened over a period of time, called chronic dos- ing. Analysis of tissue samples postmortem would also be completed using AA, and it could be used to quantitate the level in the body to determine if it was metal poisoning that killed the victim.

Cases involving toxic substances have also been seen. For instance, in the early 2000s, ethyl- ene glycol, a substance once commonly found in radiator fluid, was responsible for a large number of poisonings, some accidental and some not. The Georgia Poison Control Center, for instance, had 235 cases in 2004 (Morgan, Geller, & Kazzi, 2011). The ethylene glycol is metab- olized in the body to form a toxic substance that can be lethal. The ethylene glycol has been replaced in most of these fluids with propylene glycol to try and eliminate this type of poison- ing, or in some cases a very bitter flavoring has been added to prevent accidental ingestion. As of 2012 all producers of antifreeze for automobile use have either switched to propylene gly- col or added the bitter flavoring agent. Interestingly, there have been three recent murder mysteries in which the killer used ethylene glycol in radiator fluid as the poison of choice.

Recall from Chapter 1 that Mathieu Joseph Bonaventure Orfila is often called the father of forensic toxicology. In 1840 Dr. Orfila became involved in one of the most famous (or infa- mous) cases of murder by poisoning in history, in which Marie Lafarge was convicted of poi- soning her husband, Charles, with arsenic.

Think About It

There is a wealth of knowledge communicated through the media and Internet, including information on the use of poisons. Do you feel that placing information of this nature on television and the Internet allows people too much access to informa- tion that can prove to be harmful to people?

Case Illustration: Toxicology and Murder—in the Beginning: The Lafarges

Marie married Charles Lafarge in 1839. Although she did not come from an aristocratic background, she had been sent to the best schools and had moved in the best circles. She agreed to marry Charles under the mistaken impression that he owned property and had a successful business. In fact, he was marrying Marie for her dowry, to help pay down his debts.

They moved to a run-down house owned by Charles. She was quickly disillusioned about this arrangement and encouraged Charles to go to Paris to try to raise money. While he

(continued on next page)

Case Illustration: Toxicology and Murder—in the Beginning: The Lafarges (continued)

was away in Paris, Marie sent him a Christmas cake. After eating a piece of it, he became violently ill. He discarded the remainder of the cake, but did not think about seeing a doc- tor; he thought the cake had spoiled in transit. He still did not feel well after returning home. Marie prepared his meals during this time, and he again fell ill. The family doctor thought the symptoms were “cholera-like” and was not suspicious when Marie asked him for a prescription for arsenic to kill the rats that were disturbing Charles at night. Charles’s health deteriorated rapidly, and he eventually died. His family, and others who had come to keep watch and help him, became suspicious of Marie. She had been observed stirring a white powder into food and drink intended for Charles. A doctor that was consulted close to the time Charles died began to suspect poisoning, but it was too late.

One of Charles’s brothers, whose suspicions had been aroused, contacted the local police, and a magistrate came to do an inquiry. He took possession of some food items that remained, which could contain a poison. He learned that Marie had purchased arsenic not long before Charles had received the cake in Paris and again after he returned home. Marie’s gardener confirmed that she had given him arsenic to make a paste to kill rats. This paste was found around the house, but it did not appear to have been disturbed by rats. The magistrate also asked Charles’s local doctors if they could perform a new test for arsenic that he had heard about: the Marsh test. The doctors agreed but did not know about the test’s intricacies. They used older methods to test Charles’s stomach contents taken at autopsy and obtained inconclusive results. Nevertheless, they reported arsenic present. One of the people tending to Charles had taken Marie’s box, from which people had seen her taking the white powder for Charles’s food and drink, and it was turned over to the magis- trate. Arsenic was found in the box. In addition, the arsenic paste that had been placed in the house for the rat problem was found to be a mixture of flour, water, and baking soda.

Marie was put on trial for murder. One of Marie’s lawyers knew Dr. Orfila. He submitted the local doctors’ arsenic testing results to Orfila and asked for an opinion. Orfila submitted an affidavit to the trial court stating that the tests had been conducted poorly and that the result meant nothing. When the local doctors testified about the arsenic in Charles’s body, the lawyer read Orfila’s affidavit informing the court about the Marsh test and insisted that he be called to do the test and as a witness. Prosecutors were confident of Marie’s guilt and said they would agree to the testing, but they did not see the necessity of calling Orfila (who was the acknowledged expert on the Marsh test in Europe at the time). The judge agreed and ordered that local pharmacists conduct the testing. They reported not finding any arsenic in the stomach contents taken at autopsy. Charles’s body was then exhumed and new specimens taken. The pharmacists again failed to find arsenic. Marie seemed to be vindicated.

However, the prosecutor learned from Orfila’s writings that arsenic can leave the stom- ach through normal digestive processes and thus not be present in the contents. He also remembered the saved food items that Marie had given to Charles. He asked that they be tested. The defense, now confident about their case, agreed. This time, though, the pharma- cists came back and said there was a large amount of arsenic in the food items. The pros- ecutor again asked the judge to permit Orfila to come in and settle the matter, since there had been contradictory results. The defense more or less had to agree to this, having con- sulted Orfila first. Orfila conducted his tests in the presence of the pharmacists and found that arsenic was present in specimens taken from Charles’s body. The defense team sought to call an opposing expert, François Raspail, who had opposed Orfila in court at other

(continued on next page)

© 2019 Bridgepoint Education, Inc. All rights reserved. Not for resale or redistribution.

Section 5.2Poisons

This was a spectacular case in the annals of criminal justice. People were divided on whether Marie was guilty. It was also one of the first cases pitting experts against one another in the courtroom—something that is quite common today.

Poisoning is now infrequent in murder cases. A couple of centuries ago, it was used often by the aristocracy to get rid of their enemies. A modern murder by poison took place in 2000 in San Diego, California. This case is intriguing because it involves employees of the medical examiner’s forensic toxicology laboratory. For more on this case, see the Case Illustration box later in this section.

Pesticides Pesticides are not usually seen in forensic toxicology cases. A common class of pesticides is the organophosphates; these compounds include parathion and diazinon. Most of these cases involve accidental exposures. Should a case be seen that is suspicious, blood and urine sam- ples can be analyzed in the forensic toxicology laboratory.

Chromatographic techniques can provide preliminary information about a sample through separation of the different components of a mixture. If you put a drop of ink near the bottom of a piece of paper and then dip the paper in water, the water will be absorbed and travel up the paper. When the water hits the ink, some of the pigments will continue upward with the water, while others remain behind. As the water continues to travel up the paper, you can see separation of the ink pigments. This works the same way with forensic samples when put through instrumentation that is often used. By separating a mixture such as urine into its individual components and comparing these to known pesticides, we can say that a pes- ticide could be present in the urine, and if so, it might be a particular pesticide as opposed to many others.

Mass spectroscopy will then be used to conclusively identify the pesticide that was ingested by the victim and found in the urine. Remember from Chapter 4 that mass spectroscopy can give molecular information that will allow the scientist to say without doubt that a partic- ular pesticide, such as malathion, is present, as opposed to any other pesticide that exists. Hospitals can determine this class of compound is involved based on symptoms, including salivation, lacrimation (tears), excessive urination, diarrhea, nausea, and vomiting. Testing is then completed to determine if organophosphate class compounds are present. Should the circumstances of the poisoning be suspicious, law enforcement will be called. Samples should be collected with proper chain of custody and sent to the forensic science laboratory.

Case Illustration: Toxicology and Murder—in the Beginning: The Lafarges (continued)

times. Unfortunately for Marie, Raspail was late, and the trial ended. Marie was convicted and sentenced to life imprisonment. Suffering from tuberculosis, Marie was released in 1852 but died the same year.

Reflect On It In what ways do you think this case would be different today, in terms of determining the pres- ence of arsenic in Charles’s body, the court proceedings, and the verdict?

© 2019 Bridgepoint Education, Inc. All rights reserved. Not for resale or redistribution.

Section 5.2Poisons

Carbon Monoxide Carbon monoxide (CO) is encountered mainly in accidental deaths. This odorless, colorless gas binds to hemoglobin (the protein in red blood cells that carries oxygen) so tightly that it cannot be easily displaced. As more and more hemoglobin is rendered useless by binding to CO, oxygen deprivation will set in and can cause death. Most of the approximately 500 deaths from CO in the United States each year are due to malfunctioning flame heaters and a lack of CO detectors in homes, and they are termed unintentional deaths (CDC, 2007). Suicide by CO poisoning using automobiles used to be common, though this is becoming less popular as other methods of CO poisoning, such as by charcoal, have been found (Schmitt, Williams, Woodard, & Harruff, 2011). Carbon monoxide is formed when organic fuels are burned with too little oxygen present to form carbon dioxide (CO2). Levels of less than 1.5% CO in the air can be lethal within minutes. In the lab, a CO-oximeter will be used to measure the level of carboxyhemoglobin in the blood to determine if the cause of death was CO poisoning.

Other Gases Toxicology laboratories are encountering other gases in samples from law enforcement agencies. Many of these submissions are due to intentional inhalation of various substances for the purposes of getting high. Included in this group are the inhalants discussed in Chapter 4. These are the nitrites and nitrates; anesthetic gases like nitrous oxide and halo- thane; and the fluoro- and chlorocarbon compounds, such as difluoroethane, found in office supplies and pressurizers for food products. These compounds are easily purchased and abused. Users inhale the contents as they spray them from the can. The ingredients enter the bloodstream very quickly through the lungs. The effects are similar to central nervous system depressants. An officer on the scene may find a user unresponsive, but he or she will revive in minutes, and the compounds will clear from the bloodstream very quickly. Due to the rapid clearing of the compounds from the system, obtaining samples for prosecution of cases is difficult, since most of the drug will clear from the user’s system on the way to a collection site such as a hospital.

These compounds do not show up in Breathalyzer testing and will not be seen in the urine under normal testing, so a blood sample is best for cases involving inhalants. In the labora- tory, the sample will be tested using headspace gas chromatography with mass spectroscopy. This is the same technique used to find ethanol in the blood; it can easily differentiate and conclusively identify various inhalants for the courts.

Illicit Drugs and Medications Illicit drugs and medications are commonly seen in toxicology cases. These also involve sam- ples taken from living beings and samples taken postmortem. In the case of drugs, testing will include the use of chromatography of various types, color tests, and immunoassay as the preliminary testing to determine the classes of drugs that might be present. Extraction of the sample is completed to purify the sample. Final identification of the drugs is accomplished with mass spectroscopy as the conclusive test. Blood and urine samples are the most com- mon, though hair testing is on the rise. In postmortem cases, other samples will be collected, including vitreous humor (fluid in the eye) and possibly tissue samples. While collecting fluid from the eye may seem unusual or even disgusting, for the toxicologist, the vitreous humor is a sample that is cleaner than samples like blood or even urine, because there are fewer

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