Laboratoire de sciences judiciaires et de médecine légale, 1701 Parthenais, Montréal, Québec, H2K 3S7, Canada.
Forensic Sci Int Genet. 2019 Jan;38:9-14. doi: 10.1016/j.fsigen.2018.10.002. Epub 2018 Oct 4.
In many sexual assault cases, bedding and clothing are essential pieces of evidence that are screened for semen stains to gather DNA from the assailant. In some cases, these items have been washed before being seized and sent to the forensic lab. However, few data exist on the optimal methods for detecting and sampling semen stains on washed fabrics. In this paper, we used semen stains washed up to six times to evaluate the efficiency of commonly used screening methods for the detection of semen: alternate light source (ALS), acid phosphatase (AP), prostate specific antigen (PSA) and microscopy (sperm Hy-Liter, SHL). We also assessed different washing conditions (detergents, washing machines, addition of bleach) and sampling methods (cutting and swabbing). The results show that some semen stain detection strategies, such as ALS, PSA, and SHL, are effective even when the item was washed multiple times. We also show that a complete genetic profile could be obtained from semen stains washed six times. Based on these findings, we present different strategies for the detection and sampling of semen stains depending on the circumstances of the case.
在许多性侵犯案件中，被褥和衣物是重要的证据，需要对精液污渍进行筛查，以从袭击者身上获取 DNA。在某些情况下，这些物品在被扣押并送往法医实验室之前已经被清洗过了。然而，关于在已清洗织物上检测和采样精液污渍的最佳方法的数据很少。在本文中，我们使用已清洗多达六次的精液污渍来评估常用于检测精液的常用筛查方法的效率：交替光源（ALS）、酸性磷酸酶（AP）、前列腺特异性抗原（PSA）和显微镜（精子 Hy-Liter，SHL）。我们还评估了不同的洗涤条件（洗涤剂、洗衣机、添加漂白剂）和采样方法（切割和擦拭）。结果表明，即使物品被多次清洗，一些精液污渍检测策略，如 ALS、PSA 和 SHL，仍然有效。我们还表明，可以从已清洗六次的精液污渍中获得完整的遗传图谱。基于这些发现，我们根据案件情况提出了不同的检测和采样精液污渍的策略。
