Glass-containing gunshot residues and particles of industrial and occupational origins: Considerations for evaluating GSR traces

Kelsey E. Seyfang, Nick Lucas, Kahlee E. Redman, Rachel S. Popelka-Filcoff, Hilton J. Kobus, K. Paul Kirkbride

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

In an ideal case, the value of traces would be determined numerically and presented through the use of likelihood ratios or verbal-equivalent scales. A problem in the evaluation of gunshot residue (GSR) evidence using these models is that in many shooting scenarios insufficient data exist to support a quantitative model of interpretation. The complex relationship that exists between ammunition composition and post-firing residues makes quantitative interpretation more difficult for GSR than for other traces such as glass. When evaluating the significance of traces in a quantitative model, the value of a trace is reduced as the number of random sources that could produce the trace increases. Previously published works have suggested that glass-containing GSR (gGSR), which is glass encrusted with lead (Pb) and barium (Ba) residues, are a new type of GSR not already classified under ASTM E1588 – 17. If random sources of particles resembling gGSR are rare, then gGSR may be valuable evidentiary traces. In order to potentially incorporate these particles into a future model, the general background prevalence of gGSR and specific sources capable of producing similar particles must be understood. Therefore, particles from fireworks, matches, and cartridge actuated nail guns were assessed on an individual basis and at a population level. These sources, known to produce particles resembling GSR, were assessed using backscattered electron – scanning electron microscopy – energy dispersive X-ray spectroscopy analysis (BSE-SEM-EDS) for the presence of glass-containing particles that resemble gGSR. In the experiments described in this article the nail gun produced particles compositionally indistinguishable from gGSR, due to the primer in the brand of nail gun cartridges used containing glass as the frictionator in addition to Pb and Ba compounds. In this study, no particles were located from fireworks or matches that were indistinguishable from gGSR, nor was any evidence observed or found in the literature that would suggest that such particles could be formed.

Original languageEnglish
Pages (from-to)284-297
Number of pages14
JournalForensic Science International
Volume298
DOIs
Publication statusPublished - 1 May 2019

Keywords

  • Cartridge discharge
  • Fireworks
  • Gunshot residue (GSR)
  • Matches
  • Nail gun
  • SEM-EDS

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