A new lab method can see chemicals in an individual fingerprint — everything from dirt, paint, ink, spilled caffeine to incriminating particles of explosives.
Using infrared spectroscopy, the technique is a ‘chemical photograph’ of traces on a person’s hands. The print is examined at different depths to distinguish between chemicals in a print and those already on a surface
Investigators already gather DNA from prints and identify drugs in sweat.
Now fingerprints reveal where you’ve been and what you’ve eaten.