(Re-)positionning forensic research & development for increased impact in gunshot residue examination

Abstract

Despite its relatively high cost and time-consuming analysis, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS) has been the “gold standard” technique for analysing inorganic gunshot residue (GSR) particles for more than 40 years. Conversely, research has largely focused on developing new techniques and innovations that have struggled to gain acceptance in routine GSR examination.This study aims to explore the persistent gap perceived between research and practice in the field of GSR, specifically why research continues to propose novel instrumental analyses that are not adopted in practice. This question was examined through a comprehensive literature review, a survey of GSR examination, and a round table organised at the annual meeting of the European Network of Forensic Science Institutes (ENFSI) Expert Working Group (EWG) Firearms / GSR in Brussels in 2023.The literature review highlighted that publications on GSR have steadily increased over the past 20 years, followed by a slight decrease after 2020 to reach approximately 40 publications in 2022. In that year, 42 % of the relevant publications focused on the development of novel methods, while 26 % addressed issues related to GSR persistence, prevalence, and interpretation.Survey responses from 45 GSR experts confirmed that residues are mainly collected from hands with carbon stubs and analysed by SEM-EDS. Among respondents, 90 % work in accredited laboratories, and 95 % have little time for research beyond routine duties. While practical innovations have largely concentrated on the optimisation of current approaches, experts strongly support collecting additional forensic data on persistence, prevalence, and secondary transfer. However, such data often suffer from a lack of harmonisation and are only indirectly useful for the interpretation, which is gradually shifting from source to activity inferences.Both practitioners and academics advocate for increased collaboration to define and conduct more impactful GSR research. However, addressing the identified barriers may require systemic changes that go beyond simply increasing resources.