(NIST: Gaithersburg, MD) -- You may have seen it on CSI: The star examines hair from a crime scene and concludes its color or texture looks like the defendant’s hair, or maybe his dog’s. Case closed.

But looks can be deceiving, as well as vague and subjective. In real life, the FBI is now reviewing thousands of cases involving hair comparisons going back to the 1980s because traditional identifications—often based on looks alone—have been called into question.

Instead, what if investigators could precisely measure a hair’s mechanical properties—its stiffness and stickiness? In fact, they can, according to recent experiments at the National Institute of Standards and Technology (NIST), which is developing science-based methods to help ensure rigorous forensic practices.

“Lots of forensics is based on the how the evidence looks,” NIST engineer Frank DelRio says. “We are trying to add another dimension, how things feel. How an object feels—its mechanical response—depends on the material and the object’s history.”

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