Forensic Analysis of Gunshot Residue

As a criminal investigator, you need to reconstruct crime scenes where firearms were used. Determining whether it was homicide or suicide, or who may have shot the firearm might be critical to a case.

Qualified forensic experts may be able to assist you with such investigations through the use of gunshot residue analysis. Gunshot residue (GSR) is particles that originate from partially reacted components of explosive primer and propellant as well as the bullet, cartridge case, and the firearm.

During forensic analysis, you can find GSR on the hands, hair and clothing of a person who has recently discharged a firearm, on an entrance wound of a victim, or on any other persons and objects that have been in the vicinity of the crime scene. Particles can be collected from a suspected shooter’s hand, for example, by using sample mounts (stubs) or adhesive tapes.

Depending on their shape, GSR particle size vary from sub-micrometers (μm) to several hundred µm in diameter. Unique GSR particles show a specific chemical signature; most commonly the combination of lead, barium, and antimony. In addition, GSR particles from lead-free type ammunition (Sintox) can be examined.

Scanning electron microscopes with energy dispersive x-ray spectroscopy allow the identification of very small amounts of GSR particles and the subsequent analysis of the surface morphology and composition of individual GSR particles with high accuracy.