Investigation of the use of luminescent markers as gunshot residue indicators

The addition of luminescent markers into ammunition cartridges is an appealing proposal to achieve a greater individual identification of the ammunition. The lanthanide elements present in these luminescent materials act as characteristic chemical markers that, also, offer the great benefit of making gunshot residues (GSR) collection easier. In this work, conventional ammunition cartridges tagged with two types of luminescent markers were shot. Then, the particles produced were visualized under UV light on the floor, clothing targets and the shooter. The luminescent particles spread over the floor determined the shooter position and the bullet trajectory. The illumination of the shot targets allows the visualization of the GSR patterns only using a portable UV lamp, avoiding the use of colorimetric test. The GSR particles were collected and subjected to SEM-EDX and Raman spectroscopy analysis to get information about their inorganic and organic composition. The results indicated that part of the marker and the GSR merge and travel together. With this, particles composed by the marker and propellant organic compounds can be identified by Raman spectroscopy, and the unequivocal identification of the GSR and the marker can be achieved by SEM-EDX. Consequently, the luminescent particles detected under UV light improve the evidence collection and offer information about the GSR and the marker.Ministerio de Economía y Competitividad (MINECO