AFTE Store - Quantitative High-Resolution 3D Microscopy Improves Confidence When Determining the Order of Creation of Toolmarks

We address the problem of determining the order of creation of engravures (toolmarks) on spent cartridges and fired bullets. We employ quantitative high resolution large area 3D optical imaging for traceable comparison. This solution is novel in the sense that so far only qualitative 2D imaging has been used to address this issue. Our main result is that we can now determine the order of creation of two different kinds of toolmarks on spent cartridges. The main impact of the result is that this technique improves the investigator’s confidence when determining the order of creation of the marks as well as the direction of the engravure. Our work advances the state of the art in the field of forensic toolmark inspection by enabling a new quantitatively measured dimension (2D->3D) to improve the objectivity of the forensic analysis. Our work was carried out on copper that was scratched with a steel stylus in a controlled manner. The method was validated using spent cartridges. In practice this effort could aid inspection work aiming at telling apart marks created by the cartridge manufacturer from those made by the gun that fired the cartridge.