On the cutting edge of reform for forensic textile damage examinations

Abstract

Strategies to reduce the prevalence of knife crime are being implemented worldwide. However, research into the forensic examination of stabbings, particularly in relation to the magnitude of the problem, is lacking. Textiles are ubiquitous in everyday life, thus are often physically damaged during crimes such as assault or homicide. Textile damage resulting from these crimes is routinely investigated in forensic laboratories to identify the type of damage present (e.g. cut or tear) and the possible mechanism by which the damage was created. When a weapon such as a knife is submitted in the case of a stabbing, it is tested to evaluate whether it could have caused the damage observed in the evidential garment. While simulation experiments follow a documented protocol, testing is typically performed manually using a biological skin simulant, thereby leaving the protocol at risk of uncontrolled variations. This thesis aims to optimise the simulation testing framework to strengthen the validity of the textile damage discipline. Improving the standardisation of examinations will provide an opportunity to reform contemporary laboratory protocols. This research demonstrates that a synthetic skin simulant and a custom-built stabbing machine are both suitable for integration into a forensic laboratory examination scheme. Textile damage examinations are, by necessity, largely reliant upon the opinion, experience and professional judgement of the practitioner. Practitioners derive their opinions from a range of sources, including empirical data. However, a key challenge associated with textile damage science compared with other forensic disciplines is the lack of empirical data. This thesis is aimed at generating empirical data to improve the foundational knowledge underpinning practitioner opinions. Data from two human stabbing performance trials were evaluated and compared against those from an instrumented stabbing device. Certain aspects of stab events were investigated, showing that the type of weapon influences the action used and that forensic experts and laypeople perform simple stabbing simulation tests similarly. A study of the effect of various knife blade features on textile damage showed that knives with broad or rounded tips, despite the sharpness of the blade, rarely penetrated the substrate. Overall, the research findings will enhance the investigation of knife crime and, importantly, highlight an avenue for future knife manufacture that will reduce the lethality and medical severity of sharp force trauma.

Date of Award	2024
Original language	English
Supervisor	James ROBERTSON (Supervisor), Wayne SPRATFORD (Supervisor) & Macarthur Fergusson (Supervisor)