The persistence of semen on cotton fabric in various water environments

ABSTRACT

Biological evidence that can generate a DNA profile is considered highly important evidence in sexual assault cases. As ejaculate evidence is unlikely to be found on intimate swabs after 24 hours, textile evidence is of significant importance in such cases. Fabric garments may be exposed to water, potentially to remove evidence, or due to the location of a decedent. To determine the effects of exposure to various water types, semen-stained cotton underwear was exposed to tap, swimming pool, river, and ocean water for up to two weeks. For detection of semen stains, narrow-band, fixed wavelength lighting was minimally successful, while acid phosphatase testing with an extended cut-off was highly sensitive. Spermatozoa were undetectable on fabric samples soaked in ocean water for 12 hours, and swimming pool water for one week, with no upper limit of detectability noticed for tap or river water, although a decreasing trend was noted.

KEYWORDS:

• Spermatozoa
• semen
• acid phosphatase
• sexual assault
• forensic biology

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Murdoch University Master of Forensic Science (Professional Practice).