Measuring changes in drug particulate on evidence packaging due to routine case analysis

The presence of drug residue and drug background in a forensic context continues to be of interest for a variety of reasons. While prior work has studied the presence of these residues on laboratory surfaces and on drug evidence, the contribution of residue on the exterior of drug packaging from the analysis process itself has not yet been studied. This work aims to qualitatively and quantitively identify what, if any, effect the analysis of drug evidence has on drug residue levels on the exterior of the evidence packaging. Using wipe collection techniques, samples from the exterior of drug evidence packaging were taken prior to opening cases and after repackaging to measure changes in residue composition and mass. A total of 64 submissions were analyzed, and an increase in drug residue mass was observed 85.5% of the time. After analysis and repackaging, 95% of packages had detectable drug residue on their exterior even though some of the cases were repackaged into new bags. Drug residue masses on the exterior of drug packaging were found to be as high as tens of micrograms. The presence of drug residue on the exterior of drug evidence packaging is expected given the collection and analysis procedures, therefore potential ways to minimize these levels are currently being studied. The presence of these residues is an important factor to consider when developing protocols for the entire evidence handling process and its impact on personnel – from evidence handling technicians to crime scene technicians to submitting officers.