New Fingerprinting Technique Reignites Cold Cases
Scientists in Britain have developed a new method to fight crime by allowing police to lift fingerprints from bullets, even after a criminal wipes down a shell casing.
Law enforcement authorities in the U.S. and Britain have already used the new technique to re-open three cold cases.
John Bond, the physicist who developed the technique, said police are now optimistic of solving one such case, a double murder that occurred in the United States.
"In one case there was enough evidence that could lead to an identification of an offender," Bond, a researcher at the University of Leicester and consultant at Northamptonshire Police in Britain, told Reuters.
The traditional method of lifting fingerprints, which has been around for more than a century, includes creating a chemical reaction with the sweat left behind on an object.  With this, an image can then be produced that the police can use.
However, if a criminal wipes away the sweat, there is little left to react with the chemical, rendering the conventional method useless, Bond told Reuters.
The new technique allows police to outsmart criminals, and produce a fingerprint even in the absence of a sweat impression.
The method focuses on tiny bits of corrosion that sweat often leaves on certain metals in bombs and bullets. Bond said the British experts covered the metal with a fine powder before applying a strong electrical charge that makes the dust stick to the corroded areas. This allowed for the production of a potential fingerprint. Â
"That very fine powder only sticks to the metal where it is corroded, which means it is only sticking where the fingerprint is and means you see the image of the fingerprint," said Bond.
However, the method is not perfect, added Bond, since some people do not secrete an adequate amount of salt in their sweat to corrode the metal enough to obtain a print.
But for some seemingly dead-end cases, the technique may provide critical evidence, and allow police to identify the person who loaded a gun used in a particular crime, Bond said.
In Kingsland, Georgia, Detective Christopher King sought the British team’s assistance to crack an unsolved 10-year-old double murder case. King said the new technique had revitalized the investigation.
"The results are surprising but to say that I am pleased would be an underestimate," he said in a statement.
"I feel very optimistic."
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