Criminalistics

DEFINITION: Use of scientific principles in the evaluation of physical evidence to detect, analyze, and solve crimes.

SIGNIFICANCE: Criminalists work in various professional settings, but they have a common goal: to use the evidence from crime scenes to tell the stories of what happened there in order to link offenders with crime victims and scenes. Criminalists analyze and interpret various forms of physical evidence and then disseminate their findings in reports that can be used by law-enforcement officers, lawyers, judges, and juries.

The term criminalistics is often used interchangeably with forensic science, and may be broadly interpreted as the science of policing or the profession of forensic science. A narrower definition of criminalistics focuses on the use of scientific principles in the evaluation of physical evidence of crimes. Science has an important role to play in the criminal justice system, and this role continues to develop and change as technology advances and improves the techniques available for investigating crimes. Criminalistics is a broad field that incorporates the use of the scientific method in the processing of evidence and the investigation of crimes.

The practitioners of criminalistics, known as criminalists, work in many different settings and in a variety of professions. Some work in crime labs as medical professionals, dentists (forensic odontologists), chemists, toxicologists, biologists, geneticists, physicists, geologists, or anthropologists, whereas others work as researchers in university settings. Generally, criminalists have some specialized training in science as it is applied to the recognition, collection, analysis, and preservation of physical evidence from crime scenes. Criminalists may also be found in courtrooms as expert witnesses, providing to help juries understand the science behind particular findings concerning evidence.

Work of Criminalists and Criminologists

The discipline of criminalistics is often confused with the discipline of criminology, but the two differ in several ways. Although both criminalists and criminologists seek to understand the patterns and truth behind criminal activities, they use different approaches and ultimately have different goals. Criminalists seek to examine evidence to detect class and individual characteristics. The ultimate goal of a criminalist is to link three things: a victim, a crime scene, and an offender. The physical evidence that may be found at a may be invisible to the naked eye, such as fingerprints; it may be minute trace evidence, such as fibers from the clothing or the environment of the offender; or it may be as obvious as a body and a pool of blood. The job of the criminalist is to uncover the story that the evidence has to tell.

The investigative tasks in which criminalists are involved are widely varied. For example, a criminalist in a crime lab may examine the chemistry of inks in a threatening letter to identify the types of materials used in an effort to determine the origin of the letter. Another criminalist may apply techniques of forensic chemistry to understand the use of drugs in a investigation. Yet another may examine fragments of a broken taillight from a hit-and-run accident, with the goal of identifying class characteristics that can be used to identify the type of vehicle from which the taillight came. In such a case, the criminalist’s next job may be to look for individual characteristics in the evidence that could link it to a specific vehicle.

Criminologists are also interested in understanding why and how crime occurs, but they do not usually examine and evaluate the physical evidence left at crime scenes to try to link crimes to specific persons or specific groups. Rather, criminologists examine psychological and sociological causes of crime, such as mental illness, low cognitive abilities, certain personality traits, socioeconomic disadvantage, poor neighborhood conditions, and dysfunctional families. Criminologists often try to understand why crime occurs and attempt to predict who is at risk to engage in criminal endeavors by finding patterns in offending. They draw from the behavioral, social, and natural sciences as well as the humanities and use various methods to achieve these ends, including survey research methods and statistical analyses.

Criminalists ask questions, examine patterns, and analyze evidence to answer legal questions. In other words, the starting point for the criminalist is to translate legal questions into scientific research questions. The goal is to use the evidence to formulate hypotheses and test the research questions. The evidence and the questions vary depending on the crime scene, but the goal remains the same: to disseminate the findings in reports that can be used by law-enforcement officers, lawyers, judges, and juries.

Bibliography

Barnett, Peter D. Ethics in Forensic Science: Professional Standards for the Practice of Criminalistics. Boca Raton, Fla.: CRC Press, 2001.

Eckert, William G., ed. Introduction to Forensic Sciences. 2nd ed. Boca Raton, Fla.: CRC Press, 1997.

Fisher, Barry A. J. Techniques of Crime Scene Investigation. 7th ed. Boca Raton, Fla.: CRC Press, 2004.

Gaensslen, R. E., Howard A. Harris, and Henry C. Lee. Introduction to forensic Science and Criminalistics. New York: McGraw-Hill, 2008.

Girard, James E. Criminalistics: Forensic Science and Crime. Sudbury, Mass.: Jones & Bartlett, 2008.

Inman, Keith, and Norah Rudin. Principles and Practice of Criminalistics: The Profession of Forensic Science. Boca Raton, Fla.: CRC Press, 2001.

Saferstein, Richard. Criminalistics: An Introduction to Forensic Science. 9th ed. Upper Saddle River, N.J.: Pearson Prentice Hall, 2007.

Spencer, James T. Introduction to Forensic Science: The Science of Criminalistics. CRC Press, 2024, doi.org/10.4324/9781003183709.