NCJ Number
228197
Date Published
April 2009
Length
25 pages
Annotation
After discussing the scientific basis for microscopic hair examinations as a means of identifying individuals in criminal cases, this paper discusses microscopic characteristics in hair identification, the transfer and persistence of hairs, hair collection, race and body-area identification from hair, the procedure for microscopic hair comparison, studies that support microscopic hair comparison, and the DNA analysis of hairs.
Abstract
The paper advises that ignoring hairs at the crime scene limits the proper analysis of the crime scene and may leave important questions unanswered. The primary challenge of microscopic hair analysis is in the biological variation of microscopic characteristics within the hairs from a single individual. This is further complicated by the variation that exists even along the shaft of a single hair. Consequently, it is generally accepted within the forensic science community that hairs are not a means of positive identification; however, they can provide substantial information because of the variation in hair among individuals. It is generally accepted that all of the characteristics exhibited by the evidentiary hair must be represented by the hairs in the known sample in order to support a conclusion of association. The limitation of the science is that there is always the possibility of a coincidental match, because some people can share the same microscopic characteristics of their hair. Microscopic hair comparison coupled with either nuclear DNA or mitochondrial DNA analysis provide the judicial system with significantly more powerful information than either method alone; however, each technique on its own is useful. It is imperative that hair analysis be conducted by specially trained and experienced forensic analysts who can explain the process, limitations, meaning, and significance of a microscopic hair association. 78 references