NCJ Number
130307
Journal
FBI Law Enforcement Bulletin Volume: 60 Issue: 6 Dated: (June 1991) Pages: 19-22
Date Published
1991
Length
4 pages
Annotation
Gunshot primer residue (GSR) tests are valuable in that, under well-defined circumstances, they may associate an individual with a firearm.
Abstract
The two basic types of test involve neutron activation analysis or atomic absorption spectroscopy to determine the presence of barium and antimony on the hands of the suspect, and visual imaging using scanning electron microscopes equipped to conduct energy dispersive X-ray analysis. However, for the tests to be effective, officers must collect GSR evidence immediately upon making an arrest, a step that often conflicts with other standard arrest procedures. Officers must also realize that the presence of GSR does not identify a person as a shooter, but simply places him in the environment in which the shooting occurs. Conversely, the absence of GSR on an individual's hands does not mean he did not handle or fire a weapon. Accurate identification of GSR often depends on the prior experiences of the laboratory performing the analysis. GSR samples should not be collected when a person has recently been associated with a firearm, when more than a few hours have elapsed since the shooting, or when the ammunition used in the shooting does not contain both barium and antimony. 2 references