Raman Technique Detects Crime Scene Clues From Traces Of Lipstick

A smudge of lipstick can be a telltale sign. It can link a victim or suspect to a crime scene or establish that two individuals came into physical contact during a crime. But investigators’ ways of telling lipsticks apart have limitations. Forensic scientists typically rely on techniques that are destructive or require human interpretation, such as energy-dispersive X-ray analysis or HPLC. A new report shows that Raman spectroscopy, in contrast, can distinguish the brand and colors of lipstick traces in realistic crime-scene evidence without having to remove them from a clear plastic evidence bag (Anal. Methods 2013, DOI: 10.1039/c3ay41274a). This method could be an advantage for forensic scientists seeking to minimize sample contamination. Fatma Salahioglu, Michael J. Went, and Stuart J. Gibson at England’s University of Kent used Raman spectroscopy to detect characteristic vibrational fingerprints of lipsticks applied to tissues, cigarette butts, textile fibers, and glass slides. They determined conditions that minimize interference from fibers as well as the plastic in evidence bags. With lipstick analysis in the bag, so to speak, the team hopes to adapt the method to other types of cosmetic evidence.