The primary goal of this study was to examine the capabilities of Laser-Induced Breakdown Spectroscopy (LIBS) for determining shooting distance and identifying firearm discharge residue (FDR) on substrates of interest.
The central hypothesis of this research was that LIBS would improve the scientific reliability of the detection and observation of FDR. This assumption was based on the ability of LIBS to perform simultaneous multi-elemental detection of low ppm levels, LIBS’ superior selectivity, and the potential for confirmation of numerous emission species per analyte. The study found that LIBS enabled rapid and accurate chemical mapping of GSR patterns on pieces of evidence typically found at a crime scene. Chemical imaging of lead, barium, and antimony provided more objective approaches to estimation of shooting distance and bullet hole identification compared to color tests. In addition, LIBS provided improved detection of standard ammunitions and a trial detection of lead-free ammunitions; however, some challenges still exist regarding accurate detection and identification of non-toxic ammunitions. The proposed method is expected to aid in crime-scene reconstruction of criminal events that involve firearms. The superior capabilities of LIBS analysis compared to current practice increases the certainty of these examinations and improves the reliability of the information used during the investigative stage and when the evidence is presented in court.