Glowing Gunshot Residue: New Ways Light Crime Scene Clues

Crime scene investigations can soon become more accurate and efficient thanks to new ways to detect gunshot wounds. Researchers from the group Wim Noorduin (Amolf/Amsterdam University) and Arian Van Asten (University of Amsterdam) have developed a technology to convert lead particles found in gunshot wounds into luminescent semiconductors. This method is faster, more sensitive and easier to use than the current alternatives.

Forensic experts at Amsterdam Police have already tested it in real crime scene investigations. Researchers presented their discoveries at Forensic Science International on March 9th.

Clues from gunshot residue

Innovative light-emitting lead analysis methods provide an exciting opportunity for crime scene investigations. When a weapon is fired, it leaves gunshot wounds that contain lead traces in the surrounding environment, such as clothing and skin.

“Getting indications of gunshot residues at the crime scene is a great advantage and can help you answer important questions about film shooting. For example, you can determine whether the damage found was able to be determined if the damage found was caused by the found damage, and the hand.”

Police are currently sending all samples to the lab for analysis. However, the methods used there are often time-consuming, labor-intensive and require expensive equipment. “We are excited by the tests we are doing, and we hope that this will allow us to use the luminous method as evidence in real trials right away,” says Van Kralingen.

Semiconductor Technology

The new analytical methods are based on recent advances in perovskite research. Perovskites are promising materials used in applications ranging from solar cells to LEDs. A few years ago, Wim Noorduin’s research group developed an easy-to-use lead detection method based on Perovskite technology.

In this method, the reagent converts lead-containing surfaces into perovskite semiconductors. When shining on a UV lamp, the newly formed semiconductor emits a bright green glow that can be seen by the naked eye.

In 2021, Noorduin and Lukas Helmbrecht (formerly PhD students) established a startup to develop this lead testing method in a practical lead detection kit: Lumetallix. Over the past few years, many people around the world have used Lumetallix test kits to investigate their surroundings. They also report positive tests on paint dust at construction sites, for example, all kinds of objects, such as dinner plates, beer glasses.

Helmbrecht has developed a modified version of the Lumetallix reagent for forensic use. This reacts particularly well with lead atoms in gunshot wounds, producing a long-term green glow.

At the shooting range

To verify the effectiveness of this method, researchers conducted a series of controlled experiments. PhD students Kendra Adelberg and Arno van der Weiden (Amorph/UVA) visited Amsterdam’s shooting range. Adelberg said: “We used bullets from a standard 9mm full metal jacket and fired from two different pistols on cotton fabric targets placed at various distances.

“After applying the reagents, we visualized the pattern of gunshot wounds. The results revealed a clear luminescence pattern that was visible to the naked eye, even at long distances.”

During their experiments, Adelberg and her colleagues made two other notable findings. First, unlike other methods, new light-emitting techniques remain effective even after extensive cleaning of the shooter’s hands. This is important for forensic investigations, as suspects often try to tamper or exclude evidence of their involvement.

Second, bystanders standing about two meters away from the shooter also positively tested the lead traces on their hands. “These findings provide a valuable part of the puzzle when reconstructing a filming case. But positive tests also need to be interpreted with caution. That doesn’t mean they automatically fired the gun,” Adelberg says.

Who will benefit?

Researchers believe this new method is particularly beneficial for first responders who can use it to quickly screen potential suspects and witnesses to ensure important evidence.

Beyond forensic applications, the team is also investigating the possibility of this light-emitting method to detect lead contamination in environmental samples such as water and soil. Because lead is toxic and harmful to the environment, this study could have broader implications for environmental surveillance and public health.