Survey of gunshot residue prevalence on the hands of individuals from various population groups in and outside Europe
Amalía Stamouli, Ludwig Niewöhner, Magnus Larsson, Bertrand Colson, Steffen Uhlig, Lubor Fojtášek, Fátima Carina de Souza Machado, Lawrence Gunaratnam
Abstract
This paper presents the results of a study which was conducted by 32 participating forensic laboratories, mainly from Europe. In this EU-funded study the prevalence of the most common types of Gunshot Residue (GSR) particles was investigated in various subpopulations. Specimens were collected from the hands of more than 1300 persons using carbon stubs. Subsequently the stubs were analysed for the presence of PbBaSb particles using scanning electron microscopy coupled to energy dispersive X-ray analysis (SEM/EDS). An in-depth statistical evaluation of the obtained results was performed to estimate the prevalence of gunshot residue in specific sub-groups as well as in the general population. A customized logit model was applied on the present data set in order to identify important population characteristics and differences between the various subgroups. The observed variability of the results due to laboratory, country and sample effects was found to be significant indicating that these parameters should be taken into account in the interpretation of the results in casework.