Forensic Summary by Kenneth Ujevich
The random prevalence of GSR and “GSR-like” residues containing lead (Pb), barium (Ba), and antimony (Sb) in the wider population is a highly important question when considering the value of GSR evidence in court cases. The random distribution of GSR in two Australian jurisdictions – Victoria and South Australia – was determined through the collection of GSR samples and subsequent analysis using scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). A total of 289 samples were collected and analyzed using scanning electron microscopy coupled with energy dispersive X-ray microanalysis (SEM-EDS). Across all samples, three ‘characteristic’ three-component Pb/Ba/Sb particles were detected from a single subject in South Australia, corresponding to an overall prevalence of 0.3%. Two-component “consistent” particles were more prevalent, with Pb/Sb particles being the most frequently occurring, in 8% of samples, and in South Australia only. A number of samples, approximately 7%, showed populations of single element particles of Pb, Ba and Sb, which has the potential to generate a false positive for GSR if using a bulk analysis technique. The prevalence of GSR or “GSR-like” particles in this study matches closely with similar surveys conducted in other jurisdictions.
Nick Lucas, Hayley Brown, Michael Cook, Kahlee Redman, Tanith Condon, Harald Wrobel, K. Paul Kirkbride, Hilton Kobus. “A study into the distribution of gunshot residue particles in the random population.” Forensic Science International. Volume 262, May 2016, Pages 150-155, ISSN 0379-0738, http://dx.doi.org/10.1016/j.forsciint.2016.02.050.