Criminals don't just need to worry about their own fingerprints, they should also be concerned about their bullets' unique 'fingerprints'.
Anna Bradley, forensic scientist at The University of Western Australia is undertaking the world's largest bullet lead study.
"If a bullet from a crime scene can be 'fingerprinted', which means determining its elemental composition, then it can be compared to the composition of ammunition found in the suspect's car or house or in a recovered firearm," said Bradley.
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After shooting slaughtered pigs' heads with different ammunition, X-raying the skulls, extracting the lead shot and bullet fragments, Anna was able to match the extracted samples to their unique production batch with 97 per cent accuracy.
Bradley enlisted the help of two Australian ammunition manufacturers - one big, one small, each with different ways of making bullets - to test her hypothesis and found that the elemental signature of bullets remains unchanged throughout the manufacturing process.
She also collaborated with the Western Australia Police Service who provided reference ammunition to build up a data base of different bullets.
"The ammunition I was most excited about analysing was three boxes of unopened military cartridges from 1942, wrapped in twine and date-stamped. We found they had many similarities with modern ammunition, not surprisingly, as bullets are often made from recycled lead," said Bradley.