A Study of the Background Levels of Male DNA on Underpants Worn by Females

This study is the first to examine the background level of male DNA on underpants worn by females in the absence of sexual contact. Here, we examined 103 samples from the inside front of underpants from 85 female volunteers. Samples were examined for the presence of male DNA using NGM SElect and PowerPlex Y23 kits. Only five samples gave a “complete” Y-STR profile, even though 83.5% of our volunteers cohabited with a male. In all cases where a partner reference sample was available, the Y-STR profile matched the cohabiting partner. We have demonstrated that a Y-STR profile is not expected on the inside front of underpants worn by females after social contact alone. The results of this study are informative for evaluating the significance of a Y-STR profile on underpants in cases of alleged sexual assault.     

Clothing damage analysis in alleged sexual assaults--the need for a systematic approach

Clothing damage analysis is an integral part of the examinations carried out in sexual assault type cases. This analysis can be used to corroborate different versions of events and is at its most powerful in elucidating false allegation cases and consent cases. The purpose of this study was to determine to what extent people with varying levels of forensic awareness, experience and training could correctly carry out damage analysis. Two participant groups were asked to take part in this study. Group A ('forensic group') comprised participants at a forensic science conference, and Group B ('student group') comprised students undertaking a degree course in Forensic Science. Each group was given a practical workshop consisting of a lecture outlining common fabric types and general features observed in different damage types. Each participant was subsequently shown 25 pieces of 'damage' and asked to identify both the type of fabric construction (knit or weave) and the type of damage (cut, tear, rip, wear and tear). The ability to identify fabric construction and damage types varied within the two groups studied and across the groups. The forensic group performed better both in fabric and damage assessment than the student group. This paper suggests a systematic approach to clothing damage analysis to maximise the benefits that can be obtained from this area of forensic science and to minimise the subjectivity within the field.     

To Test or Not To Test?: The Value of Toxicology in a Delayed Overdose Death

A case demonstrating the necessity of thorough death investigation processes where toxicology plays an active role is presented. A 33‐year‐old white man presented to the emergency room in respiratory distress after an overdose episode where he was revived on the scene by fire rescue. His condition continued to deteriorate and he expired 6 days after the initial incident. No admission specimens were available for testing; however, there were specimens drawn 4 and 5 days after the incident. Drug paraphernalia from the scene was obtained by the laboratory through collaboration with local law enforcement. Drug paraphernalia was initially tested in the laboratory and after obtaining the results, the antemortem and postmortem specimens were tested identifying mitragynine and U‐47700, among other drugs. These results indicate the value in obtaining and testing drug paraphernalia, and the value of testing antemortem specimens even in the event of a delay.