Development of a Representative Material as an Alternative to Gunshot Residue for Transfer Studies

Following the discharge of a firearm, burned and unburned materials derived from the combustion of the primer are expelled from the openings of the firearms, and the combination of these constitute what is called gunshot residue. The evidential value of this trace evidence lies in its ability to establish links between a shooter, a firearm, a victim and a crime scene. A simplified scientometric approach was used to navigate the significant amount of gunshot residue literature present in the online scientific database Scopus and INTERPOL International Forensic Science Managers Symposium reports. This approach was used to assess publication patterns and trends of the literature, ascertain gaps in the research and identify new areas of study. Two areas were identified: the need for the development of an alternative material for gunshot residue and an increase in the understanding of the transfer of gunshot residue. Two potential alternative materials were developed and characterised under XRD, XPS and SEM-EDS. The first involved using a sol-gel technique applied for the synthesis of lead, barium and antimony oxide particles. The second method involved the implementation of laser ablation of lead as a solid target in a precursor solution (barium and antimony acetates dissolved in distilled water). The laser ablated samples demonstrated the most promise and had the closest representation to gunshot residue as particles were of a spheroidal shape and measured over 1 μm in diameter. The behaviour of these particles was investigated through transfer experiments revealing similar transfer efficiency values to those reported in gunshot residue literature.