Officers, Their Weapons and Their Hands: An Empirical Study of GSR on the Hands of Non-Shooting Police Officers

To help determine the potential of secondary gunshot residue (GSR) transfer from officers onto subjects to be tested for GSR, the presence of GSR on non-shooting patrol officers' hands were evaluated. Forty-three officers were sampled with adhesive-lift discs, which were subsequently concentrated and analyzed by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) microanalysis. GSR levels on the officers' hands were lower than expected considering that a firearm was carried and handled by all officers. Only three of the 43 officers had unique GSR particles. No officer had more than one unique GSR particle. Twenty-five of the 43 officers had no particles of GSR on their hands. Although the potential for secondary transfer contamination from an arresting officer to a subject exists, the low empirical numbers of GSR particles found on these non-shooting officers suggest that the potential for this occurrence is relatively low.