Damage of Biological Evidences in Sexual Assault Cases: A Hospital-Based Study

Abstract

Background and objective : Semen stains are the biological evidence that is important for charging individuals with sexual offenses because, for investigative purposes, there are used to verify the relationship between the offender and the victim. Therefore, the preservation and delivery of this type of physical evidence for examination is very important. The poor preservation of semen stains, including improper delivery, may affect the quality of the physical evidence and thus, may further affect additional forensic laboratory testing. This study aimed at examining the patterns of damage of specimens from sexual assault cases that can occur during storage and delivery.

Method :.The data was collected from the submission form of the specimens in sexual assault cases and the records from the receipt of physical evidence at the Laboratory of the Department of Forensic Medicine at the Faculty of Medicine at Khon Kaen University. The specimens, which were investigated, had been delivered from hospitals in the Northeast from 1 March 2011 to 31 August 2016. Analyzing the statistical relationship by binary logistic regression.

Result : The majority were cotton swabs at 97.64 percent (3,929 / 4,024), and the remaining samples consisted of glass slides at 2.36 percent (95 / 4,024). However, it was found that 1.68% (66 / 3,929) of the cotton swabs, which had been sent for examination, had been damaged by fungal contamination. In addition, every day that the period of testing was extended was found to have resulted in significantly increased fungal contamination by 1.09 times (p<0.05). Moreover, 8.42% (8/95) of the glass slides had been broken.

Conclusion : The pre-delivery process and the timely delivery of the specimens are both important. In addition, with poor preservation and slow delivery, the physical evidence, which is required for the sexual assault cases, can be damaged.