The persistence of bloodstains on buried fabrics and robustness of the leucomalachite green test in detecting aged bloodstains on buried fabrics

Abstract

Understanding the persistence and detection of bloodstains in different casework scenarios can inform the development of appropriate examination strategies, prioritisation of exhibits for DNA analysis, interpretation of test results, and evidence evaluation. This study investigated how soil burial impacts the persistence and detection of bloodstains on cotton, polyester, and wool fabrics over 9 weeks. Bloodstained fabric samples were buried in topsoil and evaluated weekly using the Leucomalachite Green (LMG) test, rated on a scale from 1 to 5 for colour intensity. Surface-level fabrics were compared to buried fabrics to assess burial effects on persistence of bloodstains and performance of the LMG test. Bloodstains on fabrics showed significant degradation and loss over a 9-week burial period, with wool being the most persistent, followed by polyester and cotton. Kruskal-Wallis H tests revealed significant differences in colour intensity scores by fabric type and burial duration (p < 0.001). Mann-Whitney U tests indicated significant differences between fabric types (p < 0.001) and notable degradation and loss from week 1 onward (p < 0.001). These findings are vital as it showed that the LMG test is not robust in detecting aged bloodstains from buried cotton and polyester textiles. Further, in combination with other blood markers (such as DNA or RNA), the persistence pattern observed using the LMG test could potentially inform the estimation of time since deposition of stains. The data generated can inform best practices for the prioritisation of buried exhibits for DNA analysis and storage of recovered buried clothing.