19-04-2025
Scientists turn gunshot residue into glowing semiconductors to crack shooting cases
If you're anything like me, you've spent hours binge-watching crime investigation dramas. Be it True Detective or Dexter, there's something about the criminal investigative genre that has a universal pull.
The eccentric officers figuring out who committed the crime with each puzzle piece falling into place makes up for an addictive viewing experience.
But in the real world, things are different.
The tools behind these investigations are evolving fast. Now, researchers have discovered a powerful way to detect gunshot residue (GSR), potentially transforming the way crime scenes are examined.
The breakthrough method, developed by researchers from the labs of Wim Noorduin (AMOLF / University of Amsterdam) and Arian van Asten (University of Amsterdam), converts lead particles in gunshot residue into a glowing semiconductor.
When exposed to UV light, these transformed particles emit a vivid green glow that's visible to the naked eye, making even faint traces of residue easy to spot.
It's not just more visually striking — it's also faster, more sensitive, and far more practical than traditional lab techniques.
This new method builds on recent advances in perovskite technology, a field best known for revolutionizing solar panels and LED lights.
Noorduin's team previously developed a perovskite-based lead detection method, which formed the foundation for Lumetallix — a start-up co-founded in 2021 by Noorduin and former PhD student Lukas Helmbrecht.
Lumetallix offers a simple lead detection kit that's already being used globally, with positive results in everything from dinnerware to construction site dust.
For the forensic twist, Helmbrecht tweaked the formula.
The updated reagent reacts especially well with the specific type of lead found in gunshot residue and gives off a long-lasting glow, ideal for investigators working in the field.
Forensic experts at the Amsterdam police force have already begun testing the light-emitting method in actual investigations.
"Obtaining an indication of gunshot residue at the crime scene is a major advantage, helping us answer key questions about shooting incidents," says Bente van Kralingen, a forensic expert with the force.
"We test for lead traces on possible bullet holes and a suspect's or a victim's clothing or hands."
Currently, evidence is typically sent to a lab for time-consuming and equipment-heavy analysis. But this new tool could allow officers to get early clues on-site.
"We're excited about the tests we're conducting, and hopefully this will allow us to use the light-emitting method soon in actual court cases as evidence," Bente adds.
To validate the technology, PhD students Kendra Adelberg and Arno van der Weijden carried out experiments at a local shooting range.
Using 9 mm pistols and cotton cloth targets, they tested how well the new reagent picked up residue at various distances. 'The results revealed well-defined luminescent patterns that were clearly visible to the naked eye, even at extended distances,' says Kendra.
More surprisingly, the glow didn't wash away even after extensive hand washing.
That's a major win in forensic contexts, where suspects often attempt to remove evidence. Even more fascinating, bystanders standing about two meters from the shooter tested positive for lead traces on their hands.
'These findings provide valuable pieces of the puzzle when reconstructing a shooting incident. But, a positive test also needs to be carefully interpreted, it does not automatically mean that you fired a gun,' Kendra points out.
The study is published in the journal Forensic Science International.
