Development of a Baseline Survey of Random Presence of Glass and Paint for the Interpretation of Evidence in the U.S. Courts

Over the last four decades, significant efforts have been devoted to the development and validation of databases, technologies, and consensus-based standards describing the significance of glass and paint as physical evidence, particularly regarding conclusions of source association or exclusion.
Driven by the NAS report and existing efforts from organizations such as the OSAC; trace examiners, academics, and the legal community are starting to have open debates on the use of more overarching interpretation approaches, beyond the source level. However, in the absence of local data regarding the prevalence of trace materials on the general public—relative to those involved in an alleged event—the application of these models in our courts would remain challenging and hardly compelling. The paucity of this fundamental information also decreases the efficiency of decisions made while collecting evidence at the crime scene and formulating significant investigative leads. Ground knowledge on how common is to find glass and paint traces in the general population, their relative incidence by material type (e.g., architectural vs. vehicle), or by location (e.g., shirt vs. footwear), are few examples of questions that should be substantiated with empirically verifiable data.

Consequently, the overall goal of this study is to obtain baseline data of the frequency of occurrence of glass and paint relevant to the U.S. territory. This project will address essential factors never evaluated before in a single and systematic study: a) information of random presence of glass and paint fragments in different metropolitan and rural areas in the United States; b) sampling from common apparels; c) sampling at high traffic locations with diverse socioeconomic and demographic conditions; d) different seasonal-related fashion; and e) full characterization of features of interest of the recovered traces by appropriate analytical techniques.

The combined expertise of our team and the strategic collaborations with examiners are crucial to the success of this study. The principal investigators and collaborators have played critical leading roles in trace evidence research and statistical interpretation. This proposal is anticipated to provide fundamental data to overcome upcoming challenges in the forensic assessment of glass and paint evidence in our criminal justice system, assisting practitioners and the trier of fact to make informed decisions. Moreover, this study will provide the knowledge base needed to fully utilize trace evidence to its authentic potential, including activity-related investigative and reconstruction leads, rather than restricting its value to source inferences.

Note: This project contains a research and/or development component, as defined in applicable law, and complies with Part 200 Uniform Requirements - 2 CFR 200.210(a)(14).

CA/NCF