Fast Screening of Firearm Discharge Residues by Laser-based Spectrochemical Methods, Electrochemical Sensors, and Chemometrics, West Virginia, 2019-2021

The detection of gunshot residue (GSR) provides valuable information in violent crimes, accidental shootings, and terrorism.
Despite the scientific validity of this discipline, there are persistent challenges regarding the speed of analysis, preservation
of the evidence, and interpretation of results. Consequently, there is a critical need to improve the discipline's turnaround
times and reliability. This study's overall purpose was to develop a comprehensive approach to overcome these significant concerns and
enhance the criminal justice system capabilities. This project developed and validated fast and reliable tests, using laser-induced breakdown spectroscopy (LIBS) and
electrochemical (EC) sensors for GSR detection. Also, statistical models were applied for the quantitative interpretation of the
evidence. The combination of LIBS and EC data permitted the accurate identification of organic and inorganic residues
(OGSR and IGSR, accuracy ranging from 92-99% depending on the subpopulation and classification models). This research focused on
developing SMARTER (Simpler, Modern, Affordable, Rapid, Transformative, Effective, and Reliable) solutions for GSR examinations.

The main objectives were:

Application of universal and expanded collection methods
Development of novel, ultrafast methods for dual detection of IGSR and OGSR
Development of modern 3D chemical imaging for crime scene reconstruction
Development of novel micro-particle GSR standards
Creation of a large population study and probabilistic interpretation framework