Forensics could match gunshot residue to type of ammunition

A new forensic technique could allow investigators to match gunshot residue to the exact type of ammunition, and even calibre of gun, used at a crime scene.

Spanish researchers at the University of Alcalá used laser Raman spectroscopy to infer precise organic signatures from the residue.

‘The ability to unequivocally identify a gunshot residue when a firearm is discharged is a very important and crucial part of crime scene investigation,’ María López-López and co-workers from Alcalá comment in the journal Analytical Chemistry.

The majority of analyses have, however, focused on inorganic components in the residue, such as lead, which are being phased out for environmental reasons.

In the most recent study, six different types of ammunition were fired at short distances into cloth targets, and the Raman spectra from the residue were measured and compared with that of unfired gunpowder ammunition.

The two sets of spectra showed high correlation, allowing the residue to be traced to the ammunition used.