title: Quantifying gunshot residues in cases of suicide: Implications for evaluation of suicides and criminal shootings.
abstract: Gunshot residue (GSR) is a valuable form of forensic trace evidence in the investigation of firearms-related suicide and crime. In order to ensure that such evidence is given appropriate evidential weighting when it comes to case investigations, the dynamics of the deposition and distribution of GSR must be understood. As the activity of the subject after firing is a major factor in the retention of GSR, cases of suicide involving a firearm provide an opportunity to assess GSR distribution where post-shooting activity is not an issue, assuming the subject had not been moved. Seventy-one cases of suicide by gunshot in South Australia between 1998 and 2014 were examined to collect data on firearm type, calibre, and gunshot residue test results. Overall, 47% of cases were found to produce GSR results that were not of high probative value, even though it was known that the shooter had fired a firearm. Of particular interest were cases involving 0.22 rimfire ammunition, for which characteristic particles are not expected due to lack of antimony present in the primer. Despite this, 64% of these cases resulted in the detection of antimony-containing, three-component particles.
authors.affiliation: Flinders University, South Australia, Bedford Park, SA, Australia. Electronic address: Nick.Lucas@flinders.edu.au.
authors.forename: Nick
authors.initials: N
authors.lastname: Lucas
authors.affiliation: Forensic Science SA, Divett Place, Adelaide, SA, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Cook
authors.affiliation: Retired Forensic Scientist, Northern Ireland Forensic Science Laboratory, United Kingdom.
authors.forename: James
authors.initials: J
authors.lastname: Wallace
authors.affiliation: Flinders University, South Australia, Bedford Park, SA, Australia.
authors.forename: K Paul
authors.initials: KP
authors.lastname: Kirkbride
authors.affiliation: Flinders University, South Australia, Bedford Park, SA, Australia.
authors.forename: Hilton
authors.initials: H
authors.lastname: Kobus
mesh_terms: D005389:Firearms / Q000706:statistics & numerical data; D044707:Forensic Sciences / Q000379:methods* / Q000592:standards; D006801:Humans; D013021:South Australia; D013405:Suicide; D014948:Wounds, Gunshot
keywords: Forensic science; Gunshot residue; Persistence; Scanning electron microscopy; Suicide