Forensic Scientists Devise a Better Method for Testing Crime-Scene Lipstick Stains


Femmes fatales, take note: Forensic chemists have found a better way to sample and test lipstick stains found at crime scenes. The researchers will present their findings tomorrow, March 14, at the national meeting of the American Chemical Society in San Diego, California.

Over the years, scientists have used a number of different techniques for lifting and analyzing lipstick prints. The problem is that many of these methods are tedious, time-consuming, and expensive—which means they’re unlikely to be used in underfunded crime labs.

The new method focuses on analyzing the lipstick itself. With so many brands, colors, and formulas out there, matching a specific lipstick to a person of interest could significantly narrow down a field of suspects. To sample the evidence, the scientists wash the stained object with two solvents, which break down the lipstick’s oils and waxes. They then use a process called gas chromatography to identify the sample’s chemical formula. They then compare it to the unique formulas of 40 different brands of lipsticks.

These techniques are effective and cheap, requiring very little specialized training. To date, the researchers have only tested the process on paper and cloth, but hope to eventually expand to glass and other surfaces.

This is very cool science, although it may not see too much use. In an email to mental_floss, lead researcher Brian Bellott, of Western Illinois University, admitted that “lipstick is one of the less common trace evidences found at a crime scene.” 

Yet because it's less common, perhaps that makes it more noticeable—which is all the more reason for all you lipstick-wearing criminals to cover your tracks. Don’t say we didn’t warn you.

Header image from YouTube // American Chemical Society