Dr walter c mccrone forensic science

Forensic Science History Paper

Describe the history and development of forensic science.
Identify the many roles of the forensic science expert as is they relate to the forensic science disciplines.
Explain the capabilities of forensic science.

Introduction

Joe Burbank/MCT/Newscom

LEARNING OBJECTIVES

After studying this chapter, you should be able to:

• Define forensic science and list the major disciplines forensic science encompasses.

• Recognize the major contributors to the development of forensic science.

• Account for the rapid growth of forensic laboratories in the past forty years.

• Describe the services of a typical comprehensive crime laboratory in the criminal justice system.

• Compare and contrast the Frye and Daubert decisions relating to the admissibility of scientific evidence in the courtroom.

• Explain the role and responsibilities of the expert witness.

• List the specialized forensic services, aside from the crime laboratory, that are generally available to law enforcement personnel.

CASEY ANTHONY: THE CSI EFFECT? Few criminal proceedings have captured the attention of the American public or have invoked stronger emotions than the Casey Anthony murder trial. How could a defendant who failed to report her two-year-old child missing for 31 days walk away scot-free from a murder conviction? This case had all the makings of a strong circumstantial case for the state. The state’s theory was that Casey used chloroform to render her daughter unconscious, placed duct tape over Caylee’s mouth and nose, and kept the body in the trunk for several days before disposing of it. Caylee’s decomposed remains were discovered more than five months after she was reported missing. Have TV forensic dramas created an environment in the courtroom that necessitates the existence of physical evidence to directly link a defendant to a crime scene? The closest the state came to a direct link was a hair found in the trunk of Casey’s car. However, the DNA test on the hair could only link the hair to Caylee’s maternal relatives: Casey, Casey’s mother (Caylee’s maternal grandmother), and Casey’s brother (Caylee’s uncle). And Caylee herself. No unique characteristics were found to link the duct tape on the body with that found in the Anthony home. No DNA, no fingerprints, no conviction. Definition and Scope of Forensic Science Forensic science, in its broadest definition, is the application of science to law. As our society has grown more complex, it has become more dependent on rules of law to regulate the activities of its members. Forensic science applies the knowledge and technology of science to the definition and enforcement of such laws. Each year, as government finds it increasingly necessary to regulate the activities that most intimately influence our daily lives, science merges more closely with civil and criminal law. Consider, for example, the laws and agencies that regulate the quality of our food, the nature and potency of drugs, the extent of automobile emissions, the kind of fuel oil we burn, the purity of our drinking water, and the pesticides we use on our crops and plants. It would be difficult to conceive of a food or drug regulation or environmental protection act that could be effectively monitored and enforced without the assistance of scientific technology and the skill of the scientific community. Laws are continually being broadened and revised to counter the alarming increase in crime rates. In response to public concern, law enforcement agencies have expanded their patrol and investigative functions, hoping to stem the rising tide of crime. At the same time, they are looking more to the scientific community for advice and technical support for their efforts. Can the technology that put astronauts on the moon, split the atom, and eradicated most dreaded diseases be enlisted in this critical battle? Unfortunately, science cannot offer final and authoritative solutions to problems that stem from a maze of social and psychological factors. However, as the content of this book attests, science occupies an important and unique role in the criminal justice system—a role that relates to the scientist’s ability to supply accurate and objective information about the events that have occurred at a crime scene. A good deal of work remains to be done if the full potential of science as applied to criminal investigations is to be realized. Because of the vast array of civil and criminal laws that regulate society, forensic science, in its broadest sense, has become so comprehensive a subject that a meaningful introductory textbook treating its role and techniques would difficult to create and probably overwhelming to read. For this reason, we have narrowed the scope of the subject according to the most common definition: Forensic science is the application of science to the criminal and civil laws that are enforced by police agencies in a criminal justice system. Forensic science is an umbrella term encompassing a myriad of professions that use their skills to aid law enforcement officials in conducting their investigations. The diversity of professions practicing forensic science is illustrated by the eleven sections of the American Academy of Forensic Science, the largest forensic science organization in the world: 1. Criminalistics 2. Digital and Multimedia Sciences 3. Engineering Science 4. General 5. Jurisprudence 6. Odontology 7. Pathology/Biology 8. Physical Anthropology 9. Psychiatry/Behavioral Science 10. Questioned Documents 11. Toxicology Even this list of professions is not exclusive. It does not encompass skills such as fingerprint examination, firearm and tool mark examination, computer and digital data analysis, and photography. Obviously, to author a book covering all of the major activities of forensic science as they apply to the enforcement of criminal and civil laws by police agencies would be a major undertaking. Thus, this book will further restrict itself to discussions of the subjects of chemistry, biology, physics, geology, and computer technology, which are useful for determining the evidential value of crime-scene and related evidence. Forensic pathology, psychology, anthropology, and odontology also encompass important and relevant areas of knowledge and practice in law enforcement, each being an integral part of the total forensic science service that is provided to any up-to-date criminal justice system. However, these subjects go beyond the intended scope of this book, and except for brief discussions, along with pointing the reader to relevent websites, the reader is referred elsewhere for discussions of their applications and techniques.1 Instead, this book focuses on the services of what has popularly become known as the crime laboratory, where the principles and techniques of the physical and natural sciences are practiced and applied to the analysis of crime-scene evidence. For many, the term criminalistics seems more descriptive than forensic science for describing the services of a crime laboratory. Regardless of his or her title—criminalist or forensic scientist—the trend of events has made the scientist in the crime laboratory an active participant in the criminal justice system. FIGURE 1-1 A scene from CSI, a forensic science television show. SUN/Newscom Prime-time television shows like CSI: Crime Scene Investigation have greatly increased the public’s awareness of the use of science in criminal and civil investigations (see Figure 1-1). However, by simplifying scientific procedures to fit the allotted airtime, these shows have created within both the public and the legal community unrealistic expectations of forensic science. In these shows, members of the CSI team collect evidence at the crime scene, process all evidence, question witnesses, interrogate suspects, carry out search warrants, and testify in court. In the real world, these tasks are almost always delegated to different people in different parts of the criminal justice system. Procedures that in reality could take days, weeks, months, or years appear on these shows to take mere minutes. This false image is significantly responsible for the public’s high interest in and expectations for DNA evidence. The dramatization of forensic science on television has led the public to believe that every crime scene will yield forensic evidence, and it produces unrealistic expectations that a prosecutor’s case should always be bolstered and supported by forensic evidence. This phenomenon is known as the “CSI effect.” Some jurists have come to believe that this phenomenon ultimately detracts from the search for truth and justice in the courtroom. History and Development of Forensic Science Forensic science owes its origins, first, to the individuals who developed the principles and techniques needed to identify or compare physical evidence and, second, to those who recognized the need to merge these principles into a coherent discipline that could be practically applied to a criminal justice system. The roots of forensic science reach back many centuries, and history records a number of instances in which individuals closely observed evidence and applied basic scientific principles to solve crimes. Not until relatively recently, however, did forensic science take on the more careful and systematic approach that characterizes the modern discipline. EARLY DEVELOPMENTS One of the earliest records of applying forensics to solve criminal cases comes from third-century China. A manuscript titled Yi Yu Ji (“A Collection of Criminal Cases”) reports how a coroner solved a case in which a woman was suspected of murdering her husband and burning the body, claiming that he died in an accidental fire. Noticing that the husband’s corpse had no ashes in its mouth, the coroner performed an experiment to test the woman’s story. He burned two pigs—one alive and one dead—and then checked for ashes inside the mouth of each. He found ashes in the mouth of the pig that was alive before it was burned, but none in the mouth of the pig that was dead beforehand. The coroner thus concluded that the husband, too, was dead before his body was burned. Confronted with this evidence, the woman admitted her guilt. The Chinese were also among the first to recognize the potential of fingerprints as a means of identification. Although cases such as that of the Chinese coroner are noteworthy, this kind of scientific approach to criminal investigation was for many years the exception rather than the rule. Limited knowledge of anatomy and pathology hampered the development of forensic science until the late seventeenth and early eighteenth centuries. For example, the first recorded notes about fingerprint characteristics were prepared in 1686 by Marcello Malpighi, a professor of anatomy at the University of Bologna in Italy. Malpighi, however, did not acknowledge the value of fingerprints as a method of identification. The first scientific paper about the nature of fingerprints did not appear until more than a century later, but it also did not recognize their potential as a form of identification. INITIAL SCIENTIFIC ADVANCES As physicians gained a greater understanding of the workings of the body, the first scientific treatises on forensic science began to appear, such as the 1798 work “A Treatise on Forensic Medicine and Public Health” by the French physician François-Emanuel Fodéré. Breakthroughs in chemistry at this time also helped forensic science take significant strides forward. In 1775, the Swedish chemist Carl Wilhelm Scheele devised the first successful test for detecting the poison arsenic in corpses. By 1806, the German chemist Valentin Ross had discovered a more precise method for detecting small amounts of arsenic in the walls of a victim’s stomach. The most significant early figure in this area was Mathieu Orfila, a Spaniard who is considered the father of forensic toxicology. In 1814, Orfila published the first scientific treatise on the detection of poisons and their effects on animals. This treatise established forensic toxicology as a legitimate scientific endeavor (see Figure 1-2). The mid-1800s saw a spate of advances in several scientific disciplines that furthered the field of forensic science. In 1828, William Nichol invented the polarizing microscope. Eleven years later, Henri-Louis Bayard formulated the first procedures for microscopic detection of sperm. Other developments during this time included the first microcrystalline test for hemoglobin (1853) and the first presumptive test for blood (1863). Such tests soon found practical applications in criminal trials. Toxicological evidence at trial was first used in 1839, when a Scottish chemist named James Marsh testified that he had detected arsenic in a victim’s body. During the 1850s and 1860s, the new science of photography was also used in forensics to record images of prisoners and crime scenes. FIGURE 1-2 Mathieu Orfila. The Granga Collection, New York LATE-NINETEENTH-CENTURY PROGRESS By the late nineteenth century, public officials were beginning to apply knowledge from virtually all scientific disciplines to the study of crime. Anthropology and morphology (the study of the structure of living organisms) were applied to the first system of personal identification, devised by the French scientist Alphonse Bertillon in 1879. Bertillon’s system, which he dubbed anthropometry, was a procedure that involved taking a series of bodily measurements as a means of distinguishing one individual from another. For nearly two decades, this system was considered the most accurate method of personal identification. Bertillon’s early efforts earned him the distinction of being known as the father of criminal identification (see Figure 1-3). Bertillon’s anthropometry, however, would soon be supplanted by a more reliable method of identification: fingerprinting. Two years before the publication of Bertillon’s system, the US microscopist Thomas Taylor had suggested that fingerprints could be used as a means of identification, but his ideas were not immediately followed up. Three years later, the Scottish physician Henry Faulds made a similar assertion in a paper published in the journal Nature. However, it was the Englishman Francis Henry Galton who undertook the first definitive study of fingerprints and developed a methodology of classifying them for filing. In 1892, Galton published a book titled Finger Prints, which contained the first statistical proof supporting the uniqueness of fingerprints and the effectiveness of his method. His book went on to describe the basic principles that would form our present system of identification by fingerprints. The first treatise describing the application of scientific disciplines to the field of criminal investigation was written by Hans Gross in 1893. Gross, a public prosecutor and judge in Graz, Austria, spent many years studying and developing principles of criminal investigation. In his classic book Handbuch für Untersuchungsrichter als System der Kriminalistik (later published in English under the title Criminal Investigation), he detailed the assistance that investigators could expect from the fields of microscopy, chemistry, physics, mineralogy, zoology, botany, anthropometry, and fingerprinting. He later introduced the forensic journal Archiv für Kriminal Anthropologie und Kriminalistik, which still reports improved methods of scientific crime detection. FIGURE 1-3 Bertillon’s system of bodily measurements used for the identification of an individual. Courtesy Sirchie Fingerprint Laboratories, Inc., Youngsville, NC, www.sirchie.com Ironically, the best-known figure in nineteenth-century forensics is not a real person but a fictional character: the legendary detective Sherlock Holmes (see Figure 1-4). Many people today believe that Holmes’s creator, Sir Arthur Conan Doyle, had a considerable influence on popularizing scientific crime-detection methods. In adventures with his partner and biographer, Dr. John Watson, Holmes was the first to apply the newly developing principles of serology (the study of blood and bodily fluids), fingerprinting, firearms identification, and questioned-document examination long before their value was recognized and accepted by real-life criminal investigators. Holmes’s feats excited the imagination of an emerging generation of forensic scientists and criminal investigators. Even in the first Sherlock Holmes novel, A Study in Scarlet, published in 1887, we find examples of Doyle’s uncanny ability to describe scientific methods of detection years before they were actually discovered and implemented. For instance, here Holmes explains the potential usefulness of forensic serology to criminal investigation: “I’ve found it. I’ve found it,” he shouted to my companion, running toward us with a test tube in his hand. “I have found a reagent which is precipitated by hemoglobin and by nothing else …. Why, man, it is the most practical medico-legal discovery for years. Don’t you see that it gives us an infallible test for blood stains? … The old guaiacum test was very clumsy and uncertain. So is the microscopic examination for blood corpuscles. The latter is valueless if the stains are a few hours old. Now, this appears to act as well whether the blood is old or new. Had this test been invented, there are hundreds of men now walking the earth who would long ago have paid the penalty of their crimes …. Criminal cases are continually hinging upon that one point. A man is suspected of a crime months perhaps after it has been committed. His linen or clothes are examined and brownish stains discovered upon them. Are they blood stains, or rust stains, or fruit stains, or what are they? That is a question which has puzzled many an expert, and why? Because there was no reliable test. Now we have the Sherlock Holmes test, and there will no longer be any difficulty.” FIGURE 1-4 Sir Arthur Conan Doyle’s legendary detective Sherlock Holmes applied many of the principles of modern forensic science long before they were adopted widely by real-life police. © Paul C. Chauncey/CORBIS. All rights reserved. TWENTIETH-CENTURY BREAKTHROUGHS The pace of technological change quickened considerably in the twentieth century, and with it the rate of advancements in forensic science. In 1901, Dr. Karl Landsteiner discovered that blood can be grouped into different categories, now recognized as the blood types A, B, AB, and O. The possibility that blood grouping could be useful in identifying an individual intrigued Dr. Leone Lattes, a professor at the Institute of Forensic Medicine at the University of Turin in Italy. In 1915, Lattes devised a relatively simple procedure for determining the blood group of the dried blood in a bloodstain, a technique that he immediately applied to criminal investigations. At around the same time, Albert S. Osborn was conducting pioneering work in document examination. In 1910, Osborn wrote the first significant text in this field, Questioned Documents. This book is still a primary reference for document examiners. Osborn’s development of fundamental principles of document examination was responsible for the acceptance of documents as scientific evidence by the courts. One of the most important contributors to the field in the early twentieth century was the Frenchman Edmond Locard. Although Hans Gross was a pioneering advocate for the use of the scientific method in criminal investigations, Locard first demonstrated how the principles enunciated by Gross could be incorporated within a workable crime laboratory. Locard’s formal education was in both medicine and law. In 1910, he persuaded the Lyons police department to give him two attic rooms and two assistants to start a police laboratory. During Locard’s first years of work, the instruments available to him were a microscope and a rudimentary spectrometer. However, his enthusiasm quickly overcame the technical and budgetary deficiencies he encountered, and from these modest beginnings, Locard conducted research and made discoveries that became known throughout the world by forensic scientists and criminal investigators. Eventually he became the founder and director of the Institute of Criminalistics at the University of Lyons, which quickly developed into a leading international center for study and research in forensic science (see Figure 1-5). Locard asserted that when two objects come into contact with each other a cross-transfer of materials occurs (Locard’s exchange principle). He strongly believed that every criminal can be connected to a crime by dust particles carried from the crime scene. This concept was reinforced by a series of successful and well-publicized investigations. In one case, presented with counterfeit coins and the names of three suspects, Locard urged the police to bring the suspects’ clothing to his laboratory. On careful examination, he located small metallic particles in all the garments. Chemical analysis revealed that the particles and coins were composed of exactly the same metallic elements. Confronted with this evidence, the suspects were arrested and soon confessed to the crime. After World War I, Locard’s successes inspired the formation of police laboratories in Vienna, Berlin, Sweden, Finland, and Holland. Locard’s exchange principle Whenever two objects come into contact with one another, materials are exchanged between them. The microscope came into widespread use in forensic science during the twentieth century, and its applications grew dramatically. Perhaps the leading figure in the field of microscopy was Dr. Walter C. McCrone. During his lifetime, McCrone became the world’s preeminent microscopist. Through his books, journal publications, and research institute, he was a tireless advocate for applying microscopy to analytical problems, particularly forensic science cases. McCrone’s exceptional communication skills made him a much-sought-after instructor, and he educated thousands of forensic scientists throughout the world in the application of microscopic techniques. Dr. McCrone used microscopy, often in conjunction with other analytical methodologies, to examine evidence in thousands of criminal and civil cases throughout his long and illustrious career. Another trailblazer in forensic applications of microscopy was U.S. Army Colonel Calvin Goddard, who refined the techniques of firearms examination by using the comparison microscope. Goddard’s work allows investigators to determine whether a particular gun has fired a bullet by comparing the bullet with another that is test-fired from the suspect’s weapon. His expertise established the comparison microscope as the indispensable tool of the modern firearms examiner. FIGURE 1-5 Edmond Locard. Collection of Roger-Viollet, The Image Works MODERN SCIENTIFIC ADVANCES Since the mid-twentieth century, a revolution in computer technology has made possible a quantum leap forward in human knowledge. The resulting explosion of scientific advances has had a dramatic impact on the field of forensic science by introducing a wide array of sophisticated techniques for analyzing evidence related to a crime. Procedures such as chromatography, spectrophotometry, and electrophoresis (all discussed in later chapters) allow the modern forensic scientist to determine with astounding accuracy the identity of a substance and to connect even tiny fragments of evidence to a particular person and place. Undoubtedly the most significant modern advance in forensic science has been the discovery and refinement of DNA typing in the late twentieth and early twenty-first centuries. Sir Alec Jeffreys developed the first DNA profiling test in 1984, and two years later he applied it for the first time to solve a crime, identifying Colin Pitchfork as the murderer of two young English girls. The same case also marked the first time DNA profiling established the innocence of a criminal suspect. Made possible by scientific breakthroughs in the 1950s and 1960s, DNA typing offers law enforcement officials a powerful tool for establishing the precise identity of a suspect, even when only a small amount of physical evidence is available. Combined with the modern analytical tools mentioned earlier, DNA typing has revolutionized the practice of forensic science (see Figure 1-6). Another significant recent development in forensics is the establishment of computerized databases to store information on physical evidence such as fingerprints, markings on bullets and shell casings, and DNA. These databases have proved to be invaluable, enabling law enforcement officials to compare evidence found at crime scenes to thousands of pieces of similar information. This has significantly reduced the time required to analyze evidence and increased the accuracy of the work done by police and forensic investigators. FIGURE 1-6 Sir Alec Jeffreys. Homer Sykes/Alamy Images Royalty Free Although this brief narrative is by no means a complete summary of historical advances in forensics, it provides an idea of the progress that has been made in the field by dedicated scientists and law enforcement personnel. Even Sherlock Holmes probably couldn’t have imagined the extent to which science is applied in the service of criminal investigation today. Quick Review • Forensic science is the application of science to criminal and civil laws that are enforced by police agencies in a criminal justice system. • The first system of personal identification was called anthropometry. It distinguished one individual from another based on a series of bodily measurements. • Forensic science owes its origins to individuals such as Bertillon, Galton, Lattes, Goddard, Osborn, and Locard, who developed the principles and techniques needed to identify and compare physical evidence. • Locard’s exchange principle states that, when two objects come into contact with each other, a cross-transfer of materials occurs that can connect a criminal suspect to his or her victim. Crime Laboratories The steady advance of forensic science technologies during the twentieth century led to the establishment of the first facilities specifically dedicated to forensic analysis of criminal evidence. These crime laboratories are now the centers for both forensic investigation of ongoing criminal cases and research into new techniques and procedures to aid investigators in the future. HISTORY OF CRIME LABS IN THE UNITED STATES The oldest forensic laboratory in the United States is that of the Los Angeles Police Department, created in 1923 by August Vollmer, a police chief from Berkeley, California. In the 1930s, Vollmer headed the first U.S. university institute for criminology and criminalistics at the University of California at Berkeley. However, this institute lacked any official status in the university until 1948, when a school of criminology was formed. The famous criminalist Paul Kirk was selected to head the school’s criminalistics department. Many graduates of this school have gone on to develop forensic laboratories in other parts of the state and country. In 1932, the Federal Bureau of Investigation (FBI), under the directorship of J. Edgar Hoover, organized a national laboratory that offered forensic services to all law enforcement agencies in the country. During its formative stages, Hoover consulted extensively with business executives, manufacturers, and scientists, whose knowledge and experience guided the new facility through its infancy. The FBI Laboratory is now the world’s largest forensic laboratory, performing more than one million examinations every year (see Figure 1-7). Its accomplishments have earned it worldwide recognition, and its structure and organization have served as a model for forensic laboratories formed at the state and local levels in the United States as well as in other countries. Furthermore, the opening of the FBI’s Forensic Science Research and Training Center in 1981 gave the United States, for the first time, a facility dedicated to conducting research toward new and reliable scientific methods that can be applied to forensic science. This facility is also used to train crime laboratory personnel in the latest forensic science techniques and methods. Despite the existence of the FBI Laboratory, the United States has no national system of forensic laboratories. Instead, many local law enforcement jurisdictions—city, county, and state—each operate their own independent crime labs. California, for example, has numerous federal, state, county, and city crime laboratories, many of which operate independently. However, in 1972 the California Department of Justice created a network of integrated state-operated crime laboratories consisting of regional and satellite facilities. An informal exchange of information and expertise occurs within California’s criminalist community through a regional professional society, the California Association of Criminalists. This organization is the forerunner of a number of regional organizations that have developed throughout the United States to foster cooperation among the nation’s growing community of criminalists. FIGURE 1-7 (a) Exterior and (b) interior views of the FBI crime laboratory in Quantico, Virginia. Charles Dharapak/AP Wide World Photos ORGANIZATION OF A CRIME LABORATORY The development of crime laboratories in the United States has been characterized by rapid growth accompanied by an unfortunate lack of national and regional planning and coordination. Approximately four hundred public crime laboratories operate at various levels of government—federal, state, county, and municipal. The size and diversity of crime laboratories make it impossible to select any one model that best describes a typical crime laboratory. Although most of these facilities function as part of a police department, others operate under the direction of the prosecutor’s or district attorney’s office, and some work with the laboratories of the medical examiner or coroner. Far fewer are affiliated with universities or exist as independent agencies in government. Laboratory staff sizes range from one person to more than one hundred, and services offered may be quite diverse or very specialized, depending on the responsibilities of the agency that houses the laboratory. THE GROWTH OF CRIME LABORATORIES Most existing crime laboratories have been organized by agencies that either foresaw their potential application to criminal investigations or were pressed by the increasing demands of casework. Several reasons explain the unparalleled growth of crime laboratories during the past forty years: Supreme Court decisions in the 1960s compelled police to place greater emphasis on securing scientifically evaluated evidence. The requirement to advise criminal suspects of their constitutional rights and their right of immediate access to counsel has all but eliminated confessions as a routine investigative tool; successful prosecution of criminal cases requires a thorough and professional police investigation, frequently incorporating the skills of forensic science experts. Modern technology has provided forensic scientists with many new skills and techniques to meet the challenges accompanying their increased participation in the criminal justice system. Coinciding with changing judicial requirements has been the staggering increase in crime rates in the United States over the past forty years. Although it seems that this factor alone could account for the increased use of crime laboratory services by police agencies, only a small percentage of police investigations generate evidence requiring scientific examination. There is one important exception, however: drug-related arrests. All illicit-drug seizures must be sent to a forensic laboratory for confirmatory chemical analysis before the case can be adjudicated. Since the mid-1960s, drug abuse has accelerated to nearly uncontrollable levels and has resulted in crime laboratories being inundated with drug specimens. A more recent contributor to the growth and maturation of crime laboratories has been the advent of DNA profiling. Since the early 1990s, this technology has progressed to the point of individualization or near-individualization of biological evidence. That is, traces of blood, semen stains, hair, and saliva residues left behind on stamps, cups, bite marks, and so on, can be positively linked to a criminal. To meet the demands of DNA technology, crime labs have expanded staff and in many cases modernized their physical plants. The labor-intensive demands and sophisticated requirements of DNA technology have affected the structure of the forensic laboratory as has no other technology in the past fifty years. Likewise, DNA profiling has become the dominant factor in the general public’s perception of the workings and capabilities of the modern crime laboratory. In coming years thousands of forensic scientists will be added to the rolls of both public and private forensic laboratories to process crime-scene evidence for DNA and to acquire DNA profiles, as mandated by state laws, from the hundreds of thousands of individuals convicted of crimes. This endeavor has already added many new scientists to the field and will eventually more than double the number of scientists employed by forensic laboratories in the United States. A major problem facing the forensic DNA community is the substantial backlog of unanalyzed DNA samples from crime scenes. The number of unanalyzed casework DNA samples reported by state and national agencies varies from month to month but is estimated at around 100,000. In an attempt to eliminate the backlog of convicted offender or arrestee samples to be analyzed and entered into the Combined DNA Index System (CODIS), the federal government has initiated funding for in-house analysis of samples at the crime laboratory and outsourcing samples to private laboratories for analysis. Beginning in 2008, California began collecting DNA samples from all people arrested on suspicion of a felony, not just the eventual convict. The state’s database, with approximately one million DNA profiles, is already the third largest in the world, behind those maintained by the United Kingdom and the FBI. The federal government plans to begin following California’s policy. CRIME LABORATORIES IN THE UNITED STATES Historically, our federal system of government, combined with a desire to retain local control, has produced a variety of independent laboratories in the United States, precluding the creation of a national system. Crime laboratories to a large extent mirror the fragmented law enforcement structure that exists on the national, state, and local levels. The federal government has no single law enforcement or investigative agency with unlimited jurisdiction. Four major federal crime laboratories have been created to help investigate and enforce criminal laws that extend beyond the jurisdictional boundaries of state and local forces. The FBI (Department of Justice) maintains the largest crime laboratory in the world. An ultramodern facility housing the FBI’s forensic science services is located in Quantico, Virginia. Its expertise and technology support its broad investigative powers. The Drug Enforcement Administration laboratories (Department of Justice) analyze drugs seized in violation of federal laws regulating the production, sale, and transportation of drugs. The laboratories of the Bureau of Alcohol, Tobacco, Firearms, and Explosives (Department of Justice) analyze alcoholic beverages and documents relating to alcohol and firearm excise-tax enforcement and examine weapons, explosive devices, and related evidence to enforce the Gun Control Act of 1968 and the Organized Crime Control Act of 1970. The U.S. Postal Inspection Service maintains laboratories concerned with criminal investigations relating to the postal service. Each of these federal facilities offers its expertise to any local agency that requests assistance in relevant investigative matters. Most state governments maintain a crime laboratory to service state and local law enforcement agencies that do not have ready access to a laboratory. Some states, such as Alabama, California, Illinois, Michigan, New Jersey, Texas, Washington, Oregon, Virginia, and Florida, have developed a comprehensive statewide system of regional or satellite laboratories. These operate under the direction of a central facility and provide forensic services to most areas of the state. Having a regional laboratory that operates as part of a statewide system has increased the accessibility of many local law enforcement agencies to a crime laboratory, while minimizing duplication of services and ensuring maximum interlaboratory cooperation through the sharing of expertise and equipment. Local laboratories provide services to county and municipal agencies. Generally, these facilities operate independent of the state crime laboratory and are financed directly by local government. However, as costs have risen, some counties have combined resources and created multicounty laboratories to service their jurisdictions. Many of the larger cities in the United States maintain their own crime laboratories, usually under the direction of the local police department. Frequently, a large population and high crime rates combine to make a municipal facility, such as that of New York City, the largest crime laboratory in the state. CRIME LABORATORIES ABROAD Like the United States, most countries in the world have created and now maintain forensic facilities. In contrast to the U.S. system of independent local laboratories, Great Britain has developed a national system of regional laboratories under the direction of the government’s Home Office. England and Wales are serviced by regional laboratories, including the Metropolitan Police Laboratory (established in 1935), which services London. Recently, the British government announced plans to either privatize or sell off its government-operated forensic laboratories. In the early 1990s, the British Home Office reorganized the country’s forensic laboratories into the Forensic Science Service and instituted a system in which police agencies are charged a fee for services rendered by the laboratory. The fees are based on “products,” or a set of examinations that are designed to be suitable for particular types of physical evidence and are packaged together. The fee-for-service concept has encouraged the creation of a number of private laboratories that provide services to both police and criminal defense attorneys. LGC is the largest privately owned provider of forensic science services in the UK. With a staff of over 500, LGC delivers forensic services at eight laboratories in the UK. It is expected that under the planned government reorganization of state forensic laboratories, the bulk of forensic services in England and Wales will be carried out by private laboratories such as LGC. In Canada, forensic services are provided by three government-funded institutes: (1) Royal Canadian Mounted Police regional laboratories, (2) the Centre of Forensic Sciences in Toronto, and (3) the Institute of Legal Medicine and Police Science in Montreal. Altogether, more than one hundred countries throughout the world have at least one laboratory facility offering forensic science services. SERVICES OF THE CRIME LABORATORY Bearing in mind the independent development of crime laboratories in the United States, the wide variation in the services offered to different communities is not surprising. There are many reasons for this, including (1) variations in local laws, (2) the different capabilities and functions of the organization to which a laboratory is attached, and (3) budgetary and staffing limitations. In recent years, many local crime laboratories have been created solely to process drug specimens. Often these facilities were staffed with few personnel and operated under limited budgets. Although many have expanded their forensic services, some still primarily perform drug analyses. Among crime laboratories providing services beyond drug identification, the diversity and quality of services rendered varies significantly. The following forensic science units might be found in a “full-service” crime laboratory. BASIC SERVICES PROVIDED BY FULL-SERVICE CRIME LABORATORIES PHYSICAL SCIENCE UNIT The physical science unit applies principles and techniques of chemistry, physics, and geology to the identification and comparison of crime-scene evidence. It is staffed by criminalists who have the expertise to use chemical tests and modern analytical instrumentation to examine items as diverse as drugs, glass, paint, explosives, and soil. In a laboratory that has a staff large enough to permit specialization, the responsibilities of this unit may be further subdivided into drug identification, soil and mineral analyses, and examination of a variety of trace physical evidence. BIOLOGY UNIT The biology unit is staffed with biologists and biochemists who identify and perform DNA profiling on bloodstains and other dried body fluids, compare hairs and fibers, and identify and compare botanical materials such as wood and plants (see Figure 1-8). FIREARMS UNIT The firearms unit examines firearms, discharged bullets, cartridge cases, shotgun shells, and ammunition of all types. Garments and other objects are also examined to detect firearm discharge residues and to approximate how far from a target a weapon was fired. The basic principles of firearms examination are also applied to comparing marks made by tools (see Figure 1-9). DOCUMENT EXAMINATION UNIT The document examination unit studies the handwriting and typewriting on documents in question to ascertain their authenticity and/or source. Related responsibilities include analyzing paper and ink and examining indented writings (i.e., the partially visible depressions that appear on the sheet of paper that was underneath the one that was written on), obliterations, erasures, and burned or charred documents. FIGURE 1-8 A forensic scientist performing DNA analysis. Mauro Fermariello/SPL/Photo Researchers, Inc. FIGURE 1-9 A forensic analyst examining a firearm. mediacolors/Alamy Images PHOTOGRAPHY UNIT A complete photographic laboratory examines and records physical evidence. Its procedures may require the use of highly specialized photographic techniques, such as digital imaging and infrared, ultraviolet, and X-ray photography, to make invisible information visible to the naked eye. This unit also prepares photographic exhibits for courtroom presentation. OPTIONAL SERVICES PROVIDED BY FULL-SERVICE CRIME LABORATORIES TOXICOLOGY UNIT The toxicology group examines body fluids and organs to determine the presence or absence of drugs and poisons. Frequently, such functions are shared with or may be the sole responsibility of a separate laboratory facility placed under the direction of the medical examiner’s or coroner’s office. In most jurisdictions, field instruments such as the Intoxilyzer are used to determine how much alcohol an individual has consumed. Often the toxicology unit also trains operators of these instruments and maintains and services them. LATENT FINGERPRINT UNIT The latent fingerprint unit processes and examines evidence for latent fingerprints when they are submitted in conjunction with other laboratory examinations. POLYGRAPH UNIT The polygraph, or lie detector, has become an essential tool of the criminal investigator rather than the forensic scientist. However, during the formative years of polygraph technology, many police agencies incorporated this unit into the laboratory’s administrative structure, where it sometimes remains today. In any case, its functions are handled by people trained in the techniques of criminal investigation and interrogation (see Figure 1-10). VOICEPRINT ANALYSIS UNIT In cases involving telephoned threats or tape-recorded messages, investigators may require the skills of the voiceprint analysis unit to tie the voice to a particular suspect. To this end, a good deal of casework has been performed with the sound spectrograph, an instrument that transforms speech into a visual graphic display called a voiceprint. The validity of this technique as a means of personal identification rests on the premise that the sound patterns produced in speech are unique to the individual and that the voiceprint displays this uniqueness. FIGURE 1-10 An individual undergoing a polygraph test. Courtesy Woodfin Camp & Associates Sandy Schaeffer/Mai/Mai/Time Life Pictures/Getty Images CRIME-SCENE INVESTIGATION UNIT The concept of incorporating crime-scene evidence collection into the services forensic laboratories offer is slowly gaining ground in the United States. This unit dispatches specially trained personnel (civilian and/or police) to the crime scene to collect and preserve physical evidence that will be processed at the crime laboratory. Whatever the organizational structure of a forensic science laboratory may be, specialization must not impede the overall coordination of services demanded by today’s criminal investigator. Laboratory administrators need to keep open the lines of communication between analysts (civilian and uniformed), crime-scene investigators, and police personnel. Inevitably, forensic investigations require the skills of many individuals. One notoriously high-profile investigation illustrates this process: the search for the source of the anthrax letters mailed shortly after September 11, 2001. Figure 1-11 shows one of the letters and illustrates the multitude of skills required in the investigation—skills possessed by forensic chemists and biologists, fingerprint examiners, and forensic document examiners. MyCrimeKit WebExtra 1.1 Take a Virtual Tour of a Forensic Laboratory www.mycrimekit.com OTHER FORENSIC SCIENCE SERVICES Even though this textbook is devoted to describing the services normally provided by a crime laboratory, the field of forensic science is by no means limited to the areas covered in this book. A number of specialized forensic science services outside the crime laboratory are routinely available to law enforcement personnel. These services are important aids to a criminal investigation and require the involvement of individuals who have highly specialized skills. Three specialized forensic services—forensic pathology, forensic anthropology, and forensic entomology—are frequently employed at a murder scene and will be discussed at greater length when we examine crime-scene procedures in Chapter 6. Other services, such as those discussed next, are used in a wide variety of criminal investigations. FORENSIC PSYCHIATRY Forensic psychiatry is a specialized area that examines the relationship between human behavior and legal proceedings. Forensic psychiatrists are retained for both civil and criminal litigations. In civil cases, they typically perform tasks such as determining whether an individual is competent to make decisions about preparing a will, settling property, or refusing medical treatment. In criminal cases, forensic psychologists evaluate behavioral disorders and determine whether defendants are competent to stand trial. Forensic psychiatrists also examine behavior patterns of criminals as an aid in developing a suspect’s behavioral profile. FORENSIC ODONTOLOGY Practitioners of forensic odontology help identify victims based on dental evidence when the body is in an unrecognizable state. Teeth are composed of enamel, the hardest substance in the body. Because of enamel’s resilience, the teeth outlast tissues and organs during decomposition. The characteristics of teeth, their alignment, and the overall structure of the mouth provide individual evidence for identifying a specific person. Based on dental records such as X-rays and dental casts, even a photograph of the person’s smile, a set of dental remains can be matched to a suspected victim. Another application of forensic odontology to criminal investigations is bite mark analysis. Bite marks are sometimes left on a victim of assault. A forensic odontologist can compare the marks left on a victim to the tooth structure of the suspect (see Figure 1-12). FORENSIC ENGINEERING Forensic engineers are concerned with failure analysis, accident reconstruction, and causes and origins of fires and explosions. Forensic engineers answer questions such as these: How did an accident or structural failure occur? Were the parties involved responsible? If so, how were they responsible? Accident scenes are examined, photographs are reviewed, and any mechanical objects involved are inspected. FIGURE 1-11 An envelope containing anthrax spores along with an anonymous letter was sent to the office of Senator Tom Daschle shortly after the terrorist attacks of September 11, 2001. A variety of forensic skills were used to examine the envelope and letter. Also, bar codes placed on the front and back of the envelope by mail-sorting machines contain address information and information about where the envelope was first processed. Getty Images, Inc.—Getty News FIGURE 1-12 (a) A bite mark on a victim’s body. (b) Comparison to a suspect’s teeth. David Sweet, DMD, PhD, DABFP, Director BOLD Forensic Laboratory, Vancouver, BC, Canada FORENSIC COMPUTER AND DIGITAL ANALYSIS Forensic computer science is a new and fast-growing field that involves identifying, collecting, preserving, and examining information derived from computers and other digital devices, such as cell phones. Law enforcement aspects of this work normally involve recovering deleted or overwritten data from a computer’s hard drive and tracking hacking activities within a compromised system. The field of forensic computer analysis will be addressed in detail in Chapter 18. Quick Review • The development of crime laboratories in the United States has been characterized by rapid growth accompanied by a lack of national and regional planning and coordination. • Four major reasons for the increase in the number of crime laboratories in the United States since the 1960s are as follows: (1) The requirement to advise criminal suspects of their constitutional rights and their right of immediate access to counsel has all but eliminated confessions as a routine investigative tool. (2) There has been a staggering increase in crime rates in the United States. (3) All illicit-drug seizures must be sent to a forensic laboratory for confirmatory chemical analysis before the case can be adjudicated in court. (4) DNA profiling was developed and is now often required. • The technical support provided by crime laboratories can be assigned to five basic services: the physical science unit, the biology unit, the firearms unit, the document examination unit, and the photography unit. • Some crime laboratories offer optional services such as toxicology, fingerprint analysis, polygraph administration, voiceprint analysis, and crime-scene investigation. • Special forensic science services available to the law enforcement community include forensic pathology, forensic anthropology, forensic entomology, forensic psychiatry, forensic odontology, forensic engineering, and forensic computer and digital analysis. Functions of the Forensic Scientist Although a forensic scientist relies primarily on scientific knowledge and skill, only half of the job is performed in the laboratory. The other half takes place in the courtroom, where the ultimate significance of the evidence is determined. The forensic scientist must not only analyze physical evidence but also persuade a jury to accept the conclusions derived from that analysis. ANALYZING PHYSICAL EVIDENCE First and foremost, the forensic scientist must be skilled in applying the principles and techniques of the physical and natural sciences to analyze the many types of physical evidence that may be recovered during a criminal investigation. Of the three major avenues available to police investigators for assistance in solving a crime—confessions, eyewitness accounts by victims or witnesses, and the evaluation of physical evidence retrieved from the crime scene—only physical evidence is free of inherent error or bias. Criminal cases are replete with examples of individuals who were incorrectly charged with and convicted of committing a crime because of faulty memories or lapses in judgment. For example, investigators may be led astray during their preliminary evaluation of the events and circumstances surrounding the commission of a crime. These errors might be compounded by misleading eyewitness statements and inappropriate confessions. These same concerns don’t apply to physical evidence. What about physical evidence allows investigators to sort out facts as they are and not as they want them to be? The hallmark of physical evidence is that it must undergo scientific inquiry. Science derives its integrity from adherence to strict guidelines that ensure the careful and systematic collection, organization, and analysis of information—a process known as the scientific method. The underlying principles of the scientific method provide a safety net to ensure that the outcome of an investigation is not tainted by human emotion or compromised by distorting, belittling, or ignoring contrary evidence. scientific method A process that uses strict guidelines to ensure careful and systematic collection, organization, and analysis of information. The scientific method begins by formulating a question worthy of investigation, such as who committed a particular crime. The investigator next formulates a hypothesis, a reasonable explanation proposed to answer the question. What follows is the basic foundation of scientific inquiry: the testing of the hypothesis through experimentation. The testing process must be thorough and recognized by other scientists as valid. Scientists and investigators must accept the experimental findings even when they wish they were different. Finally, when the hypothesis is validated by experimentation, it becomes suitable as scientific evidence, appropriate for use in a criminal investigation and, ultimately, available for admission in a court of law. DETERMINING ADMISSIBILITY OF EVIDENCE In rejecting the scientific validity of the lie detector (polygraph), the District of Columbia Circuit Court in 1923 set forth what has since become a standard guideline for determining the judicial admissibility of scientific examinations. In Frye v. United States,2 the court ruled that, in order to be admitted as evidence at trial, the questioned procedure, technique, or principles must be “generally accepted” by a meaningful segment of the relevant scientific community. In practice, this approach requires the proponent of a scientific test to present to the court a collection of experts who can testify that the scientific issue before the court is generally accepted by the relevant members of the scientific community. Furthermore, in determining whether a novel technique meets criteria associated with “general acceptance,” courts have frequently taken note of books and papers written on the subject, as well as prior judicial decisions relating to the reliability and general acceptance of the technique. In recent years many observers have questioned whether this approach is flexible enough to deal with new scientific issues that may not have gained widespread support within the scientific community. The Federal Rules of Evidence offer an alternative to the Frye standard, one that some courts believe espouses a more flexible guideline for admitting scientific evidence. Part of the Federal Rules of Evidence governs the admissibility of all evidence, including expert testimony, in federal courts, and many states have adopted codes similar to those of the Federal Rules. Specifically, Rule 702 of the Federal Rules of Evidence sets a different standard from “general acceptance” for admissibility of expert testimony. Under this standard, a witness “qualified as an expert by knowledge, skill, experience, training, or education” may offer expert testimony on a scientific or technical matter if “(1) the testimony is based on sufficient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods reliably to the facts of the case.” In a landmark ruling in the 1993 case of Daubert v. Merrell Dow Pharmaceuticals, Inc.,3 the U.S. Supreme Court (see Figure 1-13) asserted that “general acceptance,” or the Frye standard, is not an absolute prerequisite to the admissibility of scientific evidence under the Federal Rules of Evidence. According to the Court, the Rules of Evidence—especially Rule 702—assign to the trial judge the task of ensuring that an expert’s testimony rests on a reliable foundation and is relevant to the case. Although this ruling applies only to federal courts, many state courts are expected to use this decision as a guideline in setting standards for the admissibility of scientific evidence.