Hairs, Fibers, Crime, and Evidence by Deedrick (Forensic Science Communications, July 2000)
July 2000 - Volume 2 - Number 3
Hairs, Fibers, Crime, and Evidence
Douglas W. Deedrick
Trace Evidence Unit
Federal Bureau of Investigation
The investigation and successful prosecution of individuals suspected of involvement in violent crimes often includes the identification and comparison of trace evidence. Trace evidence consists of materials or substances that are generally small in size and may be transferred when physical contact occurs between two individuals, between an individual and an object, or between two objects. Included in this evidence are hairs, textile fibers, soil, glass particles, paint chips, feather fragments, explosive residues, and other materials. Crimes that often result in these types of transfers include homicides, sexual assaults, aggravated assaults, and hit-and-run incidents.
The transfer of hairs and fibers and their discovery as trace evidence can be critical in associating a suspect to a victim or to a crime scene. Effective use of hair and fiber evidence, however, requires an understanding of its dynamic nature. Knowing how hairs and fibers can be transferred and which factors affect the significance of a hair or fiber match are important concerns of crime scene technicians, laboratory examiners, investigators, and prosecutors.