Effects of laundering on spermatozoa

Abstract

Collection of physical evidence as soon as possible after a sexual assault is important for obtaining the best evidence of the crime. Actions taken following a sexual assault, such as laundering clothing worn during the assault, may occur before evidence collection has begun, and can have an effect on the forensic laboratory analysis. The purpose of this study was to investigate the effects of laundering on spermatozoa. The effects of All®, Woolite® and bleach on sperm removal during washing, on sperm elution of previously laundered evidence samples, and on sperm transfer during washing were examined and compared. The possibility of sperm transfer between laundry loads was also investigated. Bleach was found to have a significant effect on sperm removal during simulated laundering. The use of detergents during washing did not prevent the subsequent elution of sperm with sodium dodecyl sulfate (SDS), and did not affect the amount of sperm transferred during washing. It was also found that sperm transfer between laundry loads can occur. These results should be considered when dealing with sexual assault evidence that has been laundered prior to forensic examination. Complications with DNA analysis on clothing may be possible due to the occurrence of sperm transfer during laundering either before or after a sexual assault occurs.