Targeted Non-Destructive Evidence Detection and Collection

The forensic DNA analyst needs the ability to detect and collect biological materials from an item without damaging the structural integrity of the evidence items, or possibly interfering with any future or subsequent examination that may be required. The ability to successfully detect, collect, and process individual biological samples from various evidence substrates without causing integral surface damage to the evidence item is a difficult challenge and may inhibit additional evaluations of the object. While traditional techniques are effective collection methods for biological samples, these typically leave evidence items in an altered and/or damaged state. Superior and more efficient non-destructive collection methods are needed to allow the forensic community to have a confident, non-destructive approach to evidence sampling. This project studied the use of non-destructive methodologies for the targeted collection of biological materials on common forensic evidentiary substrates. The Electrostatic Detection Apparatus (ESDA), alternative swab matrices (non-cotton swabs), adhesive evidence lifters, and the Thermal Fingerprint Developer (TFD) were each evaluated as effective non-destructive evidence processing tools. Each of the four non-destructive collection methodologies were systemically evaluated for their ability to yield DNA STR profiles from a variety of biological samples deposited on forensically relevant substrates.