A preliminary investigation of underwear as a support for condom evidence in rape and sexual assault cases

Abstract

Condom lubricants have been found to be a new type of evidence to investigate and analyze in sexual assaults and rape cases. Casework studies highlighted two main types of trace evidence supports collected from the victim and send to forensic laboratories: cotton swabs and victims’ underwear. If cotton swabs have been used in most of the recent published research papers, the underwear and the textile effects on the recovery of condom lubricants are under investigated although such studies are very important for the interpretation of the evidence, as highlighted in the Regina v. Andrew Nicholas Malkinson case.This work employed Diffuse Reflection Infrared Fourier Transform Spectroscopy (DRIFTS-FTIR) and Attenuated Total Reflectance (ATR-FTIR) to investigate the content of various feminine underwear and the effect of a laundry procedure on the recovery of any type of evidence. 7 laundry detergents and 9 slips from common brands/models were purchased for this study.No silicones were detected in the laundry detergents, which indicates they are unlikely to generate false positive in terms of detection of silicones. However, silicones were detected in most of the brand new underwear, which was found to be an issue when interpreting the evidence. The laundry procedure was found to significantly affect the evidence, with a strong decrease of the absorbance pre and post washing. Unfortunately, no trend regarding the temperature or the type of textile could be drawn.