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Forensic Identification Using Individual Chemical Signatures

NCJ Number
250878
Date Published
Author(s)
National Institute of Justice
Annotation
This is a summary description of the NIJ-funded research reported in “Forensic Identification Using Individual Chemical Signatures,“ which focuses on what can be known about suspects’ lifestyles from an analysis of chemical deposits left by a suspect from handling an item left at a crime scene.
Abstract
By touching items such as a personal cell phone, car keys, or a pen, a chemical signature is left that can reveal much about the lifestyle of the person who touched it. This is the conclusion of the project that was conducted. Using a mass spectrometer to analyze the molecules on the surface of an object possibly left by an offender at a crime scene, forensic scientists can determine whether the perpetrator wears high-end cosmetics, has a fungal infection, uses eye drops, or takes an antidepressant. Other determinations that may be made from such an analysis are whether the person smokes, uses sunscreen or anti-mosquito sprays, or recently took an antihistamine. The person’s diet of foods might also be determined. The project’s report indicates that “the external environment influences the chemical composition of the outermost layer of the skin. Our daily routines leave chemicals on skin surface originating from our surroundings and the human habitats to which we are exposed.” The research project tested 1,200 samples collected from the hands and personal objects used by 80 volunteers. The statistical analysis showed that samples collected from hands and phones of 39 individuals were significantly more similar to the hands of the owners than to other individuals. Researchers were able to match a phone to a person with 88 percent accuracy.
Date Created: July 9, 2017