New fingerprint method works on metals

LEICESTER, England, June 4 (UPI) -- British scientists say they've created a new technique for identifying fingerprints on metal in a breakthrough that could solve many cold criminal cases.

Forensic scientists at the University of Leicester, working with Northamptonshire's police scientific support unit, developed the method that enables scientists to "visualize" fingerprints even after the print itself has been removed. The technique can enhance a fingerprint that has been deposited on a spent small caliber metal cartridge case before it is fired.

"Wiping it down, washing it in hot soapy water makes no difference -- and the heat of the shot helps the process we use," said John Bond, support manager for the Northamptonshire police.

"The procedure works by applying an electric charge to a metal … which has been coated in a fine conducting powder, similar to that used in photocopiers," said Bond. "Even if the fingerprint has been washed off, it leaves a slight corrosion on the metal and this attracts the powder when the charge is applied, so showing up a residual fingerprint"

Bond's initial findings, which prompted the joint study, have been reported in the American Journal of Forensic Science.