Fingerprints can be recovered from fired bullet casings

Scientists have developed a technique for retrieving fingerprints from bullet casings and bomb fragments after they have been fired or detonated.

The chemical basis of the change is not yet clear, but Bond believes it is corrosion by chloride ions from the salt in sweat. These produce lines of corrosion along the ridges of the fingerprint residue.

In his paper he demonstrates that it is possible to recover fingerprints from a bullet casing ejected when a pistol is fired. "As you are pushing the magazine in you are actually putting a thumb print on the bullet," said Bond. "That's the person you want. That's the guy who loaded the gun."