Xiaoyu A. Zheng, Johannes A. Soons, Robert M. Thompson, Sushama P. Singh, Cerasela Constantin
In 2009, a report by the National Academies called into question, amongst other issues, the objectivity of visual toolmark identification by firearms examiners. The National Academies recommended development of objective toolmark identification criteria and error rate estimates. Industry, academia, and government laboratories are pursuing two promising approaches towards this goal: 1) development of mathematical criteria and advanced algorithms for the objective and automated identification and scoring of potential matches, and 2) supplementing traditional reflectance microscopy images with three- dimensional surface topography measurement data. Development and validation of both these approaches to objective toolmark identification are hindered by a lack of access to toolmark data sets that 1) represent the large variety of ballistic toolmarks encountered by toolmark examiners, and 2) represent challenging identification scenarios, such as those posed by consecutively manufactured firearms components. The NIST Ballistics Toolmark Research Database enables researchers to test and validate new approaches to objective, mathematics-based, toolmark identification while easing the transition to three- dimensional surface topography data. The database will provide a foundation for a scientific knowledge base on the degree of similarity that can be found between marks made by different firearms and the variability in marks made by an individual firearm. The current, 'fairly limited,' knowledge base is a fundamental barrier to the development and validation of objective mathematical similarity criteria, and associated confidence limits, applicable to a broad range of firearms and ammunition brands.