AFTE Store - A Validation of Lead Check Swabs for the Detection of Lead on Objects at a Crime Scene

The Sodium Rhodizonate Test is currently used to indicate possible bullet holes through the detection of all forms of lead (vapour, particles etc.) on objects. Lead Check swabs were developed to be a quick, safe, and easy way to detect lead on painted surfaces. Such swabs could be useful as a presumptive test for lead at crime scenes. The effectiveness of the two testing techniques on different media was compared after test firing bullets into different media (plywood, cotton clothing, denim, drywall and automobile body metal) at a distance of 1 yard. The specificity for lead of the swabs was comparedagainst different metals (copper, zinc, barium, etc.). The swabs performed equally well on all the test media used. It was also determined that although the swabs by themselves were not specific for lead, an additional treatment of the surface with a 5% solution of hydrochloric acid (HCl) allowed the swabs to be used to distinguish between lead and elements similar to lead (barium, thallium and cadmium). The conclusion was reached that the Lead Check swabs can be a useful presumptive test for lead in forensic identification and crime scene work.