Forensic Science
The word forensic is derived from the Latin word forensic—a reference to Roman court forums in which evidence of wrongdoing was presented. Modern use of the term forensics refers to scientific principles and processes that are applied in the analysis of evidence for legal purposes. Alternatively known as criminalistics, forensics involves using sophisticated techniques and tools to identify, collect, analyze, preserve, and present evidence of crimes or civil wrongdoing in legal proceedings, as well as to verify identification of deceased individuals. The essential goal of forensics analysis is to verify connections between two or more physical items, for example, the blood of a homicide victim to that found on clothes worn by a suspect. Forensics involves analysis of many other types of evidentiary items such as prescription and illicit/illegal drugs, metals, glass, plastics, fuels, paints, tire/shoe prints, tool/tool marks, and latent substances such as synthetic fibers, human hair, and animal fur, among others.
Modern forensics began with nineteenth-century efforts of Alphonse Bertillon (1853–1914), director of the Bureau of Criminal Identification of the Paris (France) Police Department, to classify and identify criminals on the basis of their physical characteristics. In 1888 Francis Galton proposed a fingerprint classification method after which fingerprinting was first used for criminal identification by Scotland Yard investigators in 1901, and by New York City detectives in 1902. By 1930 the Federal Bureau of Investigation (FBI) of the U.S. Department of Justice had established a national fingerprint classification system, and in 1946 the FBI created its Identification Division that relied extensively on burgeoning fingerprint records for suspect identification in criminal cases. Since then the FBI lab has helped solve thousands of criminal cases using many forensics analysis methods, and is among the largest and most technologically capable forensic laboratories in the world.
Types of Forensics Evidence and Analysis
There are many types of forensic methods, each of which corresponds to the kind of evidence analyzed. For example, ballistics is the study of firearms, ammunition, bombs/explosives, bullets, and other projectiles. Forensic anthropology attempts to reconstruct the likeness of decomposed or dismembered bodies based on skeletal remains and other factors. Forensic odontology matches bite marks with teeth or dental records; and forensic entomologists study corpses infested with insects to determine the approximate time of death and other information. Forensic psychology and psychiatry seek to profile criminals, and also apply social work and mental health counseling practices to investigative situations. Forensic toxicology involves analysis of intoxicants, drugs, and poisons. Forensic taphonomy pertains to the examination of dead and decaying human, animal, and plant remains.
The most modern, prominent, and scientifically promising form of forensics is DNA analysis profiling which involves comparison of deoxyribonucleic acid found in human body tissue or fluids such as blood, perspiration, urine, semen, or vaginal secretions. In addition, biometrics analysis is used in forensics to verify identification of people by comparing biological traits such as finger/palm prints and iris or retina cell patterns. Other forms of forensics involve toxicology (the study of poisons and their harmful effects), computer forensics, voiceprint identification, and polygraph examinations (lie detector testing). In addition to determining the sources of criminal evidence and matching these to known sources, forensics also involves crime scene reconstruction—examining evidence to determine the nature of activities and physical dynamics of interactions among perpetrators and crime victims, series of events, directions of travel, angles and relative forces of impact, pre/post impact trajectories, and primary versus secondary causes of harm, and more.
Fundamental and Ethical Challenges in Forensics
Primary challenges in forensics pertaining to the overall validity, reliability, and credibility of evidence presented in court cases involves:
- protecting evidence from harm before, during, and after its collection at crime scenes and in laboratories and evidence storage facilities;
- accurately analyzing evidence and truthfully presenting findings in legal proceedings to help explain how crimes occurred and the possible guilt or innocence of individuals accused of crimes;
- developing and maintaining expertise of forensics professionals through training;
- acquiring, certifying, and maintaining laboratory equipment;
- providing managerial oversight to ensure accurate analyses and truthful reporting of findings in legal proceedings;
- truthfully testifying about analytical methods, findings, and credentials of examiners;
- achieving laboratory accreditation by one or more nationally recognized professional membership associations.
Criticism of and concern about forensics analysis has involved all the challenges listed above. In addition, so-called voodoo science or junk science refers to the reality that all forms of forensics analysis require professional judgment in determining whether evidence collected at crime scenes matches known-source samples to the exclusion of all other possibilities. In many types of forensics analysis there is no scientific basis for employing statistical probability modeling to accurately estimate the chances that one or more evidentiary items are not aperfect match. Fingerprint analysis, for example, although long accepted by courts as a type of scientific evidence is actually a technical art predicated on the belief that no two people have exactly the same print patterns and that professionals conducting tests sought exculpatory evidence in addition to match points. This fundamental problem extends to other types of forensics analysis, and when combined with numerous legal cases in which forensics experts lied about their analytical findings and/or professional credentials, has resulted in considerable controversy about the reliability of evidence collection and forensics analysis procedures, and the trustworthiness of testimony in legal proceedings about forensic analysis/laboratory findings.
In Daubert v. Merrell Dow Pharmaceuticals, Inc. (1993), the U.S. Supreme Court scrutinized the field of forensics and established new legal standards regarding the admissibility of scientific evidence and expert witness testimony provided by forensics professionals. Standardized DNA evidence gathering and analysis championed by the National Institute of Justice of the U.S. Department of Justice, and acceptance of this form of truly scientific evidence by federal, state, and local level criminal justice systems, is important to the future of forensics, as are quality control standards such as those established by the American Society of Crime Lab Directors/Laboratory Accreditation Board. Ultimately the usefulness and reliability of forensics evidence in legal proceedings will depend on ethical (and potentially government regulated) use of forensics technologies in the public sector and in privately owned or operated laboratories.
Bibliography
Bevel, Tom. (1997). Bloodstain Pattern Analysis: With an Introduction to Crime Scene Reconstruction. Boca Raton, FL: CRC Press.
Cole, Simon A. (2001). Suspect Identities: A History of Criminal Identification and Fingerprinting. Cambridge, MA: Harvard University Press.
Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 US 579 (1993).
Fisher, David. (1995). Hard Evidence: How Detectives Inside the FBI's Sci-Crime Lab Have Helped Solve America's Toughest Cases. New York: Simon & Schuster.
Galton, Francis. (1888). "Personal Identification and Description." Nature 201–202.
James, Stuart H., and Jon J. Nordby, eds. (2003). Forensic Science: An Introduction to Scientific and Investigative Techniques. Boca Raton: CRC Press.
National Research Council. (1992). DNA Technology on Forensic Science. Washington, DC: National Academy Press.
Schmalleger, Frank. (2005). "The Future of Criminal Justice." In Criminal Justice Today: An Introductory Text For The Twenty-First Century, 8th edition. Upper Saddle River, NJ: Pearson/Prentice Hall.
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