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Sci-Tech

New technique could tell CSIs how old a fingerprint is

Mass spectrometry could be the key to solving more crimes by identifying how long fingerprints have been on the scene.

Everyone knows that fingerprints can form the cornerstone of a crime scene investigation. The unique arches and loops on our fingertips can let detectives know where we were and what we touched, but they're not very good at telling them when we were at a particular location. Knowing that extra detail could help convict or exonerate suspects in crime cases.

Now, a new technique created by Shin Muramoto and Edward Sisco at the National Institute of Standards and Technology in Maryland may arm investigators with that additional bit of information. Their findings were released in July in the journal Analytical Chemistry, and described in a video posted Tuesday.

The duo used a chemical analysis technique known as mass spectrometry to investigate fingerprints of different ages. What they found was that as a fingerprint gets older, chemicals within it such as palmitic acid migrate away from the ridges of the print at a predictable rate.

So far, the researchers have only published findings involving prints that were up to 4 days old, and in ideal lab conditions, but they say they've continued to track changes for months.

If they can further expand and confirm their findings, it could mean someday crime scene investigators will be able to tell how long a fingerprint has been on a surface, not just whom it belongs to -- which could trip up a perp who says, "I was in the house, sure. But I wasn't there yesterday."