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Hair combing to collect organic gunshot residues (OGSR)
William A MacCrehan1, Malinda J Layman, Janelle D Secl
1National Institute of Standards and Technology, Gaithersburg, MD 20899, USA. william.maccrehan@nist.gov
Abstract:
A protocol is presented for the collection and analysis of gunshot residues (GSR) from hair. A fine-toothed comb is used for collection of the residues. A small zip-closure bag serves as a container for both sample storage and extraction of the characteristic organic powder additives. The success of this residue recovery approach was tested on simulated shooters and victims using mannequin-supported human wig hair as well as on human shooters. Residues were collected from four weapons: a revolver and semi-automatic pistol, rifle and shotgun. One characteristic additive, nitroglycerin, was detected by capillary electrophoresis (CE) in the majority of the collection experiments.