Innovative Technique for Revealing Hidden Fingerprints on Ammunition
A team of scientists at Maynooth University in Ireland has introduced an innovative chemical technique to reveal hidden fingerprints on copper casings of ammunition, even after exposure to the intense heat generated by firing. This technique represents a significant advancement in forensic investigations, as recovering fingerprints from weapons and ammunition has been a persistent challenge for forensic experts.
Challenges of Recovering Fingerprints from Ammunition
Recovering fingerprints from weapons and ammunition has long been difficult due to the harsh conditions they endure during firing, including high temperatures, gases, and friction. These conditions often destroy any biological residues left by fingerprints, making it hard to link suspects to crime scenes. Consequently, many criminals have relied on the assumption that fired weapons cannot be traced back to individuals.
Dr. Ethna Dempsey, the lead researcher of the study, stated that the ultimate goal in forensic investigations has always been to recover fingerprints from ammunition casings after firing. He noted that the intense heat from firing typically eradicates any biological residues, but the new technique allows the detection of the fine lines of fingerprints that usually remain invisible.
Mechanism and Innovation
The new technique involves coating copper casings with a thin layer of carefully selected materials, revealing the hidden lines of fingerprints. Unlike many current forensic methods, this approach does not rely on toxic chemicals or expensive equipment. Instead, it uses environmentally friendly polymers and requires minimal energy to produce clear fingerprint images in seconds.
The process involves placing the copper casing inside an electrochemical cell filled with a chemical solution. When a low electrical voltage is applied, the chemicals are attracted to the surface, filling the tiny gaps between fingerprint lines and forming a clear, high-contrast image. The result appears almost instantly.
Dr. Colm McKeever, a co-researcher in the study, pointed out that the burnt residues left on the casing surface act as a template, allowing the deposition of specific materials between the gaps, making the fingerprints clearly visible.
Benefits and Future Potential
Tests have shown that this technique works effectively on samples up to 16 months old, demonstrating its durability. The study aims to change the current assumption in forensic investigations that firing eliminates all fingerprint traces on casings.
Dr. McKeever anticipated that this method could be used to match fingerprints to the person who loaded the weapon, not just the weapon itself. The team focused particularly on copper casings, a material traditionally resistant to fingerprint detection and the most commonly used worldwide.
The researchers believe that the test developed for detecting fingerprints on copper could be adapted for other metal surfaces, expanding the potential forensic applications from weapon-related crimes to arson investigations.
The technique relies on a device called a potentiometer, which controls the voltage and can be as portable as a mobile phone, making it possible to create a compact forensic test kit.
Conclusion
While the initial results are promising, this new method for recovering fingerprints requires further testing and validation before law enforcement agencies worldwide can adopt it. The project was supported by the Irish Research Foundation and Maynooth University and published in a leading criminology journal, marking a significant step forward in global policing and forensic investigations.