So far, forensic experts have struggled to take fingerprints from thermal paper used in ATM bills and receipts

UV light for visualisation of invisible fingerprints

A new device developed by a Leicester University researcher relies on UV light to visualise fingerprints on difficult surfaces such as ATM bills and receipts.

The technique, recently introduced at the Counter Terrorism Expo in London, promises to equip forensic experts with a new tool to fight fraud and financial crime. It enables them to take fingerprints from thermal paper which is not possible using conventional techniques.

“This new technology offers a new way of easily looking for fingerprints on an increasing source of paperwork that criminals are likely to handle when committing a variety of offences,” said John Bond from the University of Leicester’s Department of Chemistry who developed the new device.

“The light source provides non-invasive and speculative examination of thermal paper and can be carried out very quickly with the minimum of training to locate fingerprints.”

Bond previously developed a technique for fingerprint visualisation on thermal paper by applying heat. But this method proved ineffective in some types of thermal paper used in the USA and China, prompting the researcher to look for a more powerful solution.

In fact, the new method works in conjunction with the previous technique, which has been commercialised as the Hot Print System (HPS).

“The HPS can then be used to develop the fingerprint to enable capture as a digital image and if development with the HPS is faint, the light source can be used to illuminate faint prints to enhance digital capture,” Bond explained.

“Techniques like this are preferred by the police as they offer quick and easy examination of forensic items for fingerprints. Like all this work, the bottom line is helping the police to lock up the bad guys,” he added

In addition to the new fingerprint visualisation device, Bond also recently introduced an innovative tool for storage of used firearm shells. Based on a sterile container, the device ensures minimal contact with the outer surface of the casing, which is where extraneous DNA or fingerprints could be picked up, contaminating the evidence.

“Current recovery and storage methods invariably mean there is frictional contact with the packaging that can smudge or remove any material present which, as we know, is only in small amounts to start with so anything that better preserves this evidence is to be welcomed,” the researcher said.

“This invention is a natural extension to look at all aspects of evidence recovery, storage and processing rather than just focussing on evidence processing.  Having done the job for 20 years, you get an appreciation for the whole process and where the weaknesses are; this is often not appreciated by researchers who just focus on the processing part.”

The technology could lead to better retention of DNA and fingerprint material from crime scenes involving the discharge of a firearm.

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