THAT CRIME SCENE GLOW

Posted on 2025/04/18 by secret santa

“Assessing suspect involvement in shooting incidents. (A) Color marked areas for gunshot residue testing. (B) Direct lead testing on shooter’s hand showing bright green luminescence. (C) Lead testing on the hand of bystander after shooting showing moderate luminescence, and (D) weak luminescence after washing with water and soap. (E) Bystander’s hand after thorough washing still showing clear green luminescence on nails. (F) Indirect lead testing by wiping glass fiber cloth over clothing of a bystander shows bright luminescence. (G) Indirect testing of bystander’s shoe sole. (H) SEM stub after stubbing shooter’s hand showing green luminescence where lead is present.”

USING PEROVSKITE SEMICONDUCTORS
https://sciencedirect.com/science/article/pii/S0379073825000532
https://phys.org/gunshot-residue-method-illuminates-crime.html
Glowing gunshot residue: New method illuminates crime scene clues
by University of Amsterdam / April 16, 2025

“Crime scene investigation may soon become significantly more accurate and efficient thanks to a new method for detecting gunshot residues. Researchers from the groups of Wim Noorduin (AMOLF/University of Amsterdam) and Arian van Asten (University of Amsterdam) developed the technique that converts lead particles found in gunshot residue into light-emitting semiconductors.

This method is faster, more sensitive, and easier to use than current alternatives. Forensic experts at the Amsterdam police force are already testing it in actual crime scene investigations. The researchers published their findings in Forensic Science International on March 9. The innovative light-emitting lead analysis method offers exciting opportunities for crime scene investigations. When a weapon is fired, it leaves gunshot residue containing lead traces on the surrounding environment, including clothing and skin.

Bente van Kralingen, a forensic expert at the Amsterdam Police, explains, “Obtaining an indication of gunshot residue at the crime scene is a major advantage, helping us answer key questions about shooting incidents. For instance, determining whether the damage found could have been caused by a bullet and determining the relative position of a person who might have been involved in a shooting incident. We test for lead traces on possible bullet holes and a suspect’s or a victim’s clothing or hands.”

Currently, police send all samples to the lab for analysis. However, the methods used there are often time-consuming, labor-intensive, and require expensive equipment. “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,” says van Kralingen. The new analysis method builds on recent advances in perovskite research. Perovskites are a promising material used in applications ranging from solar cells to LEDs.

A few years ago, the research group of Wim Noorduin developed an easy-to-use lead detection method based on perovskite technology. In this method, a reagent converts lead-containing surfaces into a perovskite semiconductor. Shining with a UV lamp will make the newly formed semiconductor emit a bright green glow visible to the naked eye—making even small traces of lead easily detectable.

In 2021, Noorduin and Lukas Helmbrecht (formerly Ph.D. student in the group) established a start-up company to develop this lead testing method into a practical lead detection kit: Lumetallix. Over the past years, many people worldwide have been investigating their surroundings using the Lumetallix test kit.

They report positive tests in all sorts of objects, for example: dinner plates, beer glasses, but also in paint dust at construction sites. Helmbrecht developed an altered version of the Lumetallix reagent for the forensic application: one that reacts especially well with lead atoms in gunshot residue and produces a long-lasting green glow.

“Photoluminescent lead detection in gunshot residue”

To validate the effectiveness of this method, the researchers conducted a series of controlled experiments. Ph.D. students Kendra Adelberg and Arno van der Weijden (AMOLF/UvA) visited a shooting range in Amsterdam. Adelberg states, “We used standard 9 mm full metal jacket bullets and fired them from two different pistols at cotton cloth targets placed at various distances. “After applying the reagent, we visualized the gunshot residue patterns. The results revealed well-defined luminescent patterns that were clearly visible to the naked eye, even at extended distances.”

During their experiments, Adelberg and her colleagues made two other remarkable discoveries. First, unlike other methods, the new light-emitting technique remains effective even after extensive washing of the shooter’s hands. This is important for forensic investigations, as suspects often try to tamper with or remove evidence of their involvement. Second, bystanders standing approximately 2 meters away from the shooter also 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,” says Adelberg.

The researchers believe this new method will be especially beneficial to first responders, such as police officers, who can use it to rapidly screen potential suspects and witnesses to secure crucial evidence. Beyond forensic applications, the team is also exploring the potential of this light-emitting method to detect lead contamination in environmental samples such as water and soil. Since lead is toxic and harmful to the environment, this research could have broader implications for environmental monitoring and public health.”

Kendra Adelberg et al, Perovskite-based photoluminescent detection of lead particles in gunshot residue, Forensic Science International (2025). DOI: 10.1016/j.forsciint.2025.112415

“Latent fingermarks dusted with micronised Egyptian blue”

USING EGYPTIAN BLUE
https://theconversation.com/ancient-pigment-modern-forensics
https://nationalgeographic.com/explore-egyptian-blue-fingerprints
Ancient Egyptian Powder Makes Fingerprints Glow
by A.R. Williams / May 2017

“Crime scene investigators are about to get an assist from the land of the pharaohs. New research has shown that a pigment called Egyptian blue, formulated some 5,250 years ago, can be used as dusting powder to detect fingerprints on complicated surfaces. The earliest known synthetic pigment, Egyptian blue is found in some of the paint that still colors ancient statues, coffins, and tomb walls.

Modern scientists were intrigued by this long-lasting tint and figured out its chemical components decades ago. More recently they discovered that it emits near-infrared radiation when exposed to a certain kind of light. Researchers have now demonstrated the forensic potential of that rare, invisible luminescence. After a crime is committed, police may dust relevant surfaces with a powder of a contrasting color. The powder sticks to the unique features of any fingerprints, providing visual proof that an individual was there. But prints may be hard to pick out on a shiny or highly patterned surface.

That’s where Egyptian blue can make a difference. The pigment is brushed on as usual. But the surface is then photographed under a white light with a modified camera and a filter sensitive to near-infrared rays. If fingerprints exist, they glow clearly in the resulting image. One company is already marketing the powder, says Australian forensic chemist Simon Lewis, a member of the research team. “We expect it won’t be long before it’s used by law enforcement.”

PREVIOUSLY