I loved CSI growing up. The TV shows and the games were addictive for me. Was some of it thrash? Absolutely, but I’d argue technological advance is always catching up in some way, shape or form. But it’s why the new coming out of Maynooth piqued my interest.
Scientists at Maynooth University have developed a new forensic test capable of revealing fingerprints on ammunition casings, a task previously thought almost impossible.
Maynooth Leads the Way for Forensic Advancement
The research, led by Dr Eithne Dempsey and Dr Colm McKeever of Maynooth University’s Department of Chemistry, uses a unique electrochemical method to visualise fingerprints on brass casings, even after exposure to the high heat and pressure of gunfire.
Forensic investigators have long struggled to recover prints from firearms and ammunition because the heat, friction, and gases produced when a gun is fired typically destroy biological residues. As a result, ammunition casings are often discarded at crime scenes with little chance of linking them to individuals.
Dr Dempsey described “retrieving prints from fired ammunition casings” as “The Holy Grail” of forensics. Continuing to describe the challenge being caused by “the intense heat of firing destroys any biological residue”.
The Maynooth duo’s method reveals fingerprints on casings that would have otherwise remained useless to investigators.
How Does It Work?
The method involves coating brass casings with specialised non-toxic materials to make hidden fingerprint ridges visible. Unlike other approaches that require hazardous chemicals or expensive equipment, this process relies on polymers and minimal energy.
By placing a casing in an electrochemical cell and applying a small voltage, chemicals in the solution are deposited between fingerprint ridges, creating a high-contrast image within seconds.
Dr McKeever explains that “using the burnt material that remains on the surface of the casing as a stencil, we can deposit specific materials in between the gaps, allowing for the visualisation”.
Tests showed that prints could be recovered from casings up to 16 months old, highlighting the technique’s durability.
Potential Impact on Investigations
Currently, forensic analysis of ammunition casings is typically limited to linking casings to a specific firearm. The new technique could potentially allow investigators to match casings directly to individuals who handled or loaded ammunition.
The team focused on brass casings, the most widely used type globally, but believe the method could be adapted to other metallic surfaces. This opens the possibility of wider applications, from firearm-related crimes to arson investigations.
The technique makes use of a potentiostat, a small voltage-controlling device that can be made portable, raising the prospect of compact forensic testing kits in the future.
While the findings are promising, the researchers caution that further testing and validation will be required before the method can be deployed in law enforcement investigations worldwide. You can read their full paper on the topic.
