Rapid identification of semen stains in forensic investigations: STK sperm tracker

Sexual offences are complex, necessitating expertise from various forensic disciplines for proper evidence handling. Detecting semen on clothing items in forensic laboratories is also challenging, as identifying the semen donor ultimately depends on DNA analysis. Therefore, employing a reliable and robust method for identifying semen stains is crucial for convicting offenders and exonerating the innocent. Several screening and confirmatory techniques have been developed over the years; however some are known to have limited in sensitivity, specificity and time consuming. The recent increase in forensic examinations performed on rape victims has led significant advancements in existing forensic techniques, improving the ability to identify and recovery semen. In 2016, the National Institute of Scientific Police (INPS/LPS69), France collaboration with AXO Sciences, launched STK® Sperm Tracker™ an advanced technology developed to detect semen on sexual assault evidence items. The technique is reported to be rapid, sensitive, environmental friendly, easy to use, highly specific and can use as a confirmatory test for semen. The two research studies discussed and compared its performance with traditional semen identification methods, assessed its impact on subsequent techniques like DNA analysis, evaluated its effectiveness in detecting semen from vasectomized individuals, and tested its sensitivity in identifying semen on fabric and degraded stains. It was revealed that STK is more suitable than the conventional tests on semen detection, compatible with downstream applications, and can detect semen from vasectomized donors. Additionally, it demonstrated higher sensitivity in detecting semen on various fabric types and degraded semen stain, relying significant advancement in the field of forensic science in future.