Fingerprint Technique Shows What You've Eaten

For more than a century, investigators have identified suspects by looking at the unique shapes of their fingerprints, carefully noting such details as where the lines end, bifurcate, and diverge. But the few micrograms of sweat and dirt left behind in a fingerprint contain more than a physical pattern: The chemicals in the print are clues themselves, and a new technique shows promise for using this information to make more accurate fingerprint identifications.