A Novel Two-Step Method for the Detection of OrganicGunshot Residue for Forensic Purposes: Fast Fluorescence Imaging Followedby Raman Microspectroscopic Identification

Gunshot residue (GSR) is potentially key evidence during a criminal investigation of a shooting accident. Current standardized forensic science methods target the detection of inorganic GSR (IGSR). In this proof-of-concept study, a new two-step method for the detection and identification of organic GSR (OGSR) is proposed. This method utilizes highly sensitive fluorescence hyperspectral imaging of a sample area to detect potential GSR particles, followed by confirmatory identification of the detected particles using Raman microspectroscopy. In this study, two different GSR samples on adhesive tape substrates were created. One sample was made by manually placing a known amount of OGSR particles onto an adhesive tape substrate. The second sample mimicked a real crime scene situation and had an unknown number of GSR particles mounted onto an adhesive tape substrate using a most common tape-lifting procedure for the recovery of GSR from the skin of a suspect and other surfaces. These two samples were subjected...