Gunshot residue (GSR) analysis is a crucial aspect of forensic investigations, aiding crime scene investigators in identifying the presence of firearms. However, the emergence of new environmentally friendly ammunition has posed challenges for traditional GSR analysis methods. West Virginia University (WVU) forensic scientists have made groundbreaking discoveries that shed light on how gunshot residue behaves on various surfaces, including skin, hair, and fabric. These findings will enable investigators to adapt to the use of greener ammunition and make more informed decisions during crime scene examinations. Let’s delve into the details of WVU’s research and its implications for forensic laboratories.
Understanding Gunshot Residue and Its Composition
When a firearm is discharged, the primer, a component that ignites and propels the bullet, generates a cloud of particles. These particles contain inorganic compounds such as lead, barium, and antimony. Upon contact with the skin, tiny particles from this cloud remain, and their unique composition helps forensic scientists identify firearm discharge.
However, the landscape of ammunition has evolved, with manufacturers shifting towards “green” alternatives that eliminate heavy metals harmful to the environment and human health. Consequently, GSR analysis must adapt to detect not only inorganic compounds, but also organic compounds released during the firing process.
Analyzing Organic and Inorganic Compounds in GSR
To enhance the accuracy of GSR analysis, researchers at West Virginia University investigated the differences between organic and inorganic compounds in GSR. Combining information about both types of compounds provides investigators with greater confidence in their results. This research aims to bridge the gap in our understanding of organic gunshot residue and its presence in forensic investigations.
Studying the Persistence and Transfer of GSR
Led by Tatiana Trejos, an associate professor in the Department of Forensic and Investigative Science, the research team conducted experiments to examine how organic and inorganic compounds in GSR differ in their persistence on surfaces and their transfer during various activities such as running, handshaking, and washing. The team, including graduate students Courtney Vander Pyl, Kourtney Dalzell, Korina Menking-Hoggatt, and Thomas Ledergerber, published their results in a Forensic Chemistry paper.
The researchers created new and improved organic and inorganic GSR “reference standards” to accurately simulate real-world gunshot residue. They applied these particles to fabrics, the skin and hair of human volunteers, and an artificial skin product called Strat-M. They then subjected these surfaces to activities simulating real-life scenarios before measuring the remaining particles.
Validating the Use of Artificial Skin
The experiments confirmed the viability of using Strat-M as a substitute for human skin in forensic analysis. This artificial skin, widely used in fields such as pharmaceuticals and cosmetics, proved to be a consistent and safe forensic standard. It allowed researchers to test conditions that would otherwise be impractical or unsafe for human subjects.
The Persistence and Transfer of GSR
The research findings revealed important differences in the persistence and transfer of organic and inorganic GSR particles. Inorganic particles were found to persist on surfaces such as palms and sweatshirts for longer periods than organic compounds. However, they were more susceptible to being lost or transferred during common activities. For example, washing hands with soap and water and drying them with a paper towel could prevent the identification of GSR based on the analysis of lead, barium, and antimony particles.
In contrast, organic compounds had a higher likelihood of being lost from clothing during struggles or physical interactions but were less likely to transfer to others. These differences have significant implications when investigating whether an individual is a victim of suicide or homicide.
Applying the Findings in Crime Scene Investigations
The research team aims to combine these findings with another recently developed methodology that allows crime scene investigators (CSIs) to immediately analyze possible GSR at crime scenes. By providing CSIs with faster and more informative tools, the research team hopes to enhance the apprehension of offenders with solid evidence while minimizing the potential for false incarcerations.
Future Prospects
Forensic science is continually evolving, and these new avenues of research hold promise in answering complex questions relevant to judges and juries. While current GSR analysis can determine the presence of GSR, the next challenge is to determine whether a specific individual fired the gun. WVU’s research paves the way for further advancements in forensic science, aiding in the apprehension of offenders with solid evidence and minimizing the potential for wrongful convictions.
Conclusion
The WVU Forensics Lab’s groundbreaking research on gunshot residue analysis opens up new avenues for forensic investigators to adapt to the challenges posed by environmentally friendly ammunition. By studying the behavior of organic and inorganic compounds in GSR, WVU scientists have contributed valuable insights into the persistence and transfer of these particles on various surfaces. This research not only enhances GSR analysis but also provides forensic investigators with faster and more informative tools, enabling them to apprehend offenders with solid evidence. The advancements made by WVU’s forensic scientists represent a significant step forward in the field of forensic science and bring us closer to achieving justice through accurate and reliable forensic analysis.
Research Reference: Courtney Vander Pyl et al, Transfer and persistence studies of inorganic and organic gunshot residues using synthetic skin membranes, Forensic Chemistry (2023). DOI: 10.1016/j.forc.2023.100498
