Two Irish scientists have created a groundbreaking method for recovering fingerprints from fired bullet casings — something long believed to be unimaginable.
Dr. Eithne Dempsey and her former PhD student, Dr. Colm McKeever, from the Department of Chemistry at Maynooth University in Ireland, have designed a novel electrochemical process that reveals fingerprints on brass casings even after exposure to the extreme heat generated when a gun is fired.
Solving a Long-Standing Forensic Challenge
For a long time, forensic experts have struggled to retrieve fingerprints from firearms or ammunition. The acute temperatures, gas, and friction produced during gunfire typically destroy any biological residue. For this reason, many criminals have relied on the idea that fired weapons and casings couldn’t link them to against the law scene.
“The Holy Grail in forensic investigation has all the time been retrieving prints from fired ammunition casings,” said Dr. Dempsey. “Traditionally, the extreme heat of firing destroys any biological residue. Nevertheless, our technique has been in a position to reveal fingerprint ridges that may otherwise remain imperceptible.”
The research team discovered that coating brass casings with a skinny layer of specially chosen materials can expose hidden fingerprint ridges. Unlike many existing forensic methods, this approach doesn’t depend on toxic chemicals or expensive, high-powered equipment. As an alternative, it uses environmentally friendly polymers and requires little or no energy to supply clear fingerprint images in seconds.
The method works by placing a brass casing inside an electrochemical cell stuffed with a chemical solution. When a low electrical voltage is applied, the chemicals are drawn toward the surface, filling the tiny gaps between fingerprint ridges and forming a definite, high-contrast image. The result appears almost immediately.
“Using the burnt material that continues to be on the surface of the casing as a stencil, we are able to deposit specific materials in between the gaps, allowing for the visualisation,” said Dr. McKeever.
Durable Results and Recent Investigative Possibilities
Tests showed that this system also worked on samples aged as much as 16 months, demonstrating remarkable durability.
The research has significant implications for criminal investigations, where the present assumption is that firing a gun eliminates fingerprint residues on casings.
“Currently, the very best case of forensic evaluation of ammunition casings is to match it to the gun that fired it,” said Dr. McKeever. “But we hope a technique like this might match it back to the actual one that loaded the gun.”
The team focused specifically on brass ammunition casings, a substance that has been traditionally proof against fingerprint detection and is essentially the most common variety of material used globally.
The researchers consider that the test for fingerprints on brass they’ve developed may very well be adapted for other metallic surfaces, expanding its range of potential forensic applications, from firearm-related crimes to arson.
This method uses a tool called a potentiostat, which controls voltage and could be as portable as a cell phone, making it possible to create a compact forensic testing kit.
“With this method, now we have turned the ammunition casing into an electrode, allowing us to drive chemical reactions on the surface of the casing,” said Dr. McKeever.
Toward Real-World Use
Although early results are promising, the brand new fingerprint recovery method will need further testing and validation before it might probably be utilized by law enforcement agencies world wide. The project, supported by Research Ireland and Maynooth University, was recently published in a number one forensic science journal and represents a serious step forward for global policing and criminal investigation.