Gunshot residue (GSR) is a common forensic marker for the discharge of a firearm. This residue is comprised of products from the detonation of the powder inside the cartridge by the explosive primer. The common analysis for GSR is to analyze for particles of lead and other metals solids on the hands and clothes of the suspect. The method of analysis is typically electron microscopy coupled with energy-dispersive X-ray spectroscopy (EDX) because of the high sensitivity coupled with the ability to specifically identify the metal particulates obtained. Less common is the analysis of the organic gunshot residue (OGSR) which is the organic material that is dispersed. These compounds are typically less persistent and will either be absorbed by the skin or evaporate prior to analysis. However, with the development of more sensitive methods of analysis, there is increased interest in OGSR as a forensic marker. In addition, since the compounds produced are volatile, the evaporation of the compounds will occur at a predictable rate, which may allow for establishment of a timeline since detonation. This approach would be especially useful when establishing a timeline for the events that resulted in the firing of a weapon. This information would allow a forensic laboratory to identify how long ago a bullet was fired based on the analysis of the OGSR. All of this information requires an extensive database of the compounds that are produced by the various powders.

Forensic analysis of organic gun-shot residue on bullet casings

2019 Spring National Meeting

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