The sensitivity of current forensic techniques makes it feasible to obtain a DNA profile from very few cells, including those collected from items that have come into contact with one or more individuals. Therefore, it is important to collect as many cells, and hence as much DNA, from the item as possible in order to increase the chances of making an identification. Limited comparative research has been conducted on the common techniques used in forensic laboratories to collect DNA from fabric evidence. The goals of this study were to determine which method(s) is most favorable for collection of owner DNA from worn T-shirts and handler DNA from shirts that were touched during a simulated assault. Three standard methods for collecting touch DNA from fabrics were compared in this research: cutting, swabbing, and tape-lifting. Participants wore T-shirts for a minimum of six hours, some of which underwent a simulated assault. Areas that contained the most DNA and the area of assault handling were targeted for DNA recovery. DNAs were quantified, amplified, and typed using commercial STR kits. The collection methods were compared in terms of DNA quantity and quality, measured using a profile statistic. The findings demonstrate that cutting recovers the most cells, increasing DNA yields and the profile statistics of STR profiles, with Y-STR analysis being the most informative in identifying male T-shirt handlers. Implementing protocols that enhance DNA yield based on this research, supported by court-admissible profile statistics, may increase the number of biological exhibits that could be used in criminal prosecution.
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