Experiences in successive forensic analysis of GSR and DNA traces collected on a single tape lift stub.

Abstract

Gunshot residue (GSR) and deoxyribonucleic acid (DNA) analyses are used in the reconstruction of shooting incidents involving firearms. In both fields, adhesive tapes are commonly applied to recover traces. Using a simultaneous sampling approach for retrieving both types of traces from objects related to a shooting can be powerful. We present the results for DNA testing and GSR analysis using "DNA stubs" to recover both types of traces in one sampling. The analyses are successive: stubs are first examined with scanning electron microscopy for the presence of GSR and next subjected to DNA extraction and short tandem repeat (STR) typing. The results show no negative effect on the DNA and GSR results. The risk of DNA contamination during GSR analysis is addressed, showing that it is negligible. Our experiences in casework show that the approach can be successfully implemented.