Australian forensic textile damage examinations – Finding a way forward since PCAST

Textile damage examinations are requested in a range of crime types such as assault, sexual assault and homicide. They typically involve the examination of clothing for damage such as cut, tear or thermal damage, often then followed by experimental scenario testing to help ascertain the cause of the damage. Understanding the underpinning science is central to the accurate interpretation of the complex mechanism of damage formation. In a stabbing incident for example, an understanding of the dynamic relationship between the knife blade, fabric and skin (or skin simulant) is critical.Recent reports, including the President's Council of Advisors on Science and Technology (PCAST) report, have scrutinised forensic feature-based comparison techniques. Whilst textile damage was not a focus area, it can be considered a feature-based evidence class, and one which is currently largely reliant upon a practitioner's opinion, experience and professional judgement.This paper will review the current state of textile damage examinations in Australia and survey research being conducted to address the issues raised in the context of the PCAST report. The central contribution of observational data to the evidence class of textile damage will also be explored, as well as some practical measures to counter the effects of cognitive bias.     

Effect of Sterilants on Amplification and Detection of Target DNA from Bacillus cereus Spores

To conceal criminal activity of a bioterrorist or agroterrorist, the site of pathogen generation is often treated with sterilants to kill the organisms and remove evidence. As dead organisms cannot be analyzed by culture, this study examined whether DNA from sterilant‐treated Bacillus cereus spores was viable for amplification. The spores were exposed to five common sterilants: bleach, Sterilox®, oxidizer foam (L‐Gel), a peroxyacid (Actril®), and formaldehyde vapor. The spores were inoculated on typical surfaces found in offices and laboratories to test for environmental effects. It was found that the surface influenced the efficiency of recovery of the organisms. The DNA isolated from the recovered spores was successfully detected using RT‐qPCR for all treatments except for formaldehyde, by amplifying the phosphatidylinositol phospholipase C and sphingomyelinase genes. The results demonstrated that evidence from sites treated with sterilants can still provide information on the uncultured organism, using DNA amplification.