Sexual offenders are increasingly using condoms when committing their assaults, both to reduce the risk of sexually-transmitted diseases, and to avoid leaving their DNA at the crime scene. While an offender might still leave their fingerprints behind, that often only proves that they were at a given location, and not that they were involved in any wrongdoing. Researchers from the Biomedical Research Centre at Sheffield Hallam University, however, have recently developed technology that detects condom lubricant in fingerprints. If a suspect could be tied to a crime scene by their fingerprints, and be shown to have handled a condom at that location – well, they’d have a lot more explaining to do.
The process utilizes MALDI-MSI, or matrix-assisted laser desorption/ionisation mass spectrometry imaging – this allows for the analysis of fragile molecules, that fragment when subjected to more conventional ionization techniques. The Sheffield team previously researched the use of this same technology for mapping fingerprint ridge patterns.
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In lab trials, the researchers were able to identify lubricant from two major brands of condoms in fingerprints, some of which were several weeks old. It is hoped that in the future, it might even be possible to match lubricant found in fingerprints to that found in vaginal swabs from victims, or to determine the brand of condom used.
"If condom lubricant can be detected in fingermarks it would improve the evidence for the prosecution by establishing the assailant's presence at the scene and, crucially, having had contact with a condom,” said Dr. Rosalind Wolstenholme, co-author of a paper on the research. “This would enable forensic scientists to provide further support to the evidence in alleged cases of sexual assault.”