A groundbreaking adaptation of perovskite technology is poised to transform forensic analysis of gunshot residue (“GSR”), offering unprecedented speed and sensitivity. “Perovskite” refers to a class of materials with a specific crystal structure, named after the mineral calcium titanate, discovered by Russian mineralogist Lev Perovski. Traditional GSR analysis, which relies on time-consuming laboratory methods like colorimetric tests or scanning electron microscopy with energy-dispersive spectroscopy (“SEM-EDS”), often requires specialized equipment and struggles to detect traces after tampering. A new method, developed by researchers at AMOLF and the University of Amsterdam, overcomes these limitations by converting lead particles in GSR into a light-emitting perovskite semiconductor.

This innovative technique, led by Wim Noorduin (AMOLF and University of Amsterdam), Arian van Asten (University of Amsterdam), and their team, including Kendra Adelberg, Arno van der Weijden, Lukas Helmbrecht, and Diede Blaauw, uses a reagent—methyl ammonium bromide in an isopropyl-alcohol-based liquid—to transform lead-containing surfaces into a perovskite semiconductor. When exposed to UV light, this semiconductor emits a vibrant green glow visible to the naked eye, enabling rapid and straightforward detection. Published in Forensic Science International on February 28, 2025 (Volume 370, 112415), the method, known as photoluminescent lead analysis (“PL-Pb”), is faster, more sensitive, and easier to use than conventional approaches. 

Building on earlier work by Noorduin’s group, which developed a perovskite-based lead detection method for environmental safety, Noorduin and former PhD student Lukas Helmbrecht co-founded Lumetallix in 2021 to commercialize a lead testing kit. Helmbrecht refined the reagent to target the specific lead particles in GSR, creating a long-lasting glow ideal for forensic applications. The kit, already used globally to detect lead in objects like dinnerware and construction dust, has been adapted for crime scene investigations, offering high-resolution detection of GSR traces, including ricochet markings, bullet wipes, and combustion plumes. 

Experiments at an Amsterdam shooting range demonstrated the method’s exceptional capabilities. Using 9mm pistols (a Glock 19 Gen5 and a Walther P99Q NL), researchers detected well-defined luminescent GSR patterns on cotton cloth targets at distances up to 2 meters, revealing fine details like rifling patterns that aid in shooting distance estimation and crime scene reconstruction. Remarkably, the method detected GSR on shooters’ hands even after extensive washing, a significant advantage over traditional methods that struggle with disturbed evidence. Additionally, bystanders standing approximately 2 meters from the shooter tested positive for lead traces, indicating secondary GSR transfer. “These findings provide valuable pieces of the puzzle when reconstructing a shooting incident, but a positive test must be carefully interpreted, as it does not definitively indicate that a person fired a gun,” said PhD student Kendra Adelberg. 

The method’s persistence, likened to the luminol test for blood, makes it a powerful tool for detecting latent GSR traces, even when suspects attempt to remove evidence. Forensic experts with the Amsterdam Police, including Bente van Kralingen, are actively testing the kit in real-world crime scene investigations. “Obtaining an indication of gunshot residue at the crime scene is a major advantage, helping us answer key questions about shooting incidents,” van Kralingen said. They expressed hope that ongoing validation will soon allow the method to be admissible as evidence in court, though further confirmation (e.g., via SEM-EDS) is needed to meet legal standards.

This trailblazing method offers law enforcement a rapid, reliable, and highly sensitive tool for GSR detection, potentially streamlining investigations and strengthening courtroom evidence. The Amsterdam Police continue to evaluate the kit, and its versatility suggests applications beyond forensics, such as environmental lead monitoring. With ongoing global interest and testing, this perovskite-based technology could redefine forensic science, providing a faster and more effective way to illuminate the truth at crime scenes.  

Sources: Forensic Mag, Forensic Science International

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