Trace Evidence Section:

Gunshot Residue (GSR)

Gunshot Residue (GSR) are micron-sized propellant particles released after the discharge of a firearm cartridge primer. GSR can be collected from hands, clothing, vehicles, or objects that may have been exposed to a firearm/cartridge discharge or been in contact with a firearm. Samples are generally collected by touching an exposed adhesive surface of a scanning electron stub to the item in question. These particles are evaluated for morphology, as well as for the presence of lead, barium, and antimony. Samples are collected from hands, clothing, vehicles, or other surfaces to perform a gunshot residue analysis. Examiners use a Scanning Electron Microscope equipped with an Energy Dispersive Spectrometer to detect gunshot residue particles by examining each particle for the elemental composition as well as the appearance of the particle.