Defense Date
2024
Document Type
Directed Research Project
First Advisor
Stephanie Walcott
Second Advisor
Emanuele Alves
Third Advisor
Carol Babyak
Abstract
In the years between 2014 and 2022 alone, firearm-related deaths in the United States nearly doubled, increasing conversations amongst the public surrounding gun control. Gun regulations vary between states; several states, including Mississippi, not only have relaxed gun control laws but also have the highest overall firearm-related deaths. Currently, some gun-control laws are related to the type of firearm a person can purchase, concealed carry laws and processes, registration laws, and other aspects. However, many Americans believe these laws are still not enough to reduce and prevent gun violence, calling for more research surrounding the analysis of firearm-related evidence in shooting cases. Research involving inorganic gunshot residue (IGSR) typically focuses on the shooter end rather than the target material. This work seeks to create a mathematical relationship between the concentration of metals on target materials and muzzle-to-target distance with the attempt to estimate shooting distance quantitatively. Cloth samples containing IGSRs were obtained by shooting Remington UMC 9mm Luger ammunition from a Smith & Wesson M&P9 Shield semi-automatic pistol in a controlled indoor environment at varying distances. The IGSR was extracted from samples using an acid digestion procedure and analyzed using Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) to quantify barium, lead, and antimony. A mathematical model was developed for the interpretation of barium, lead, and antimony in both ammunitions analyzed. Each inorganic metal produced a unique polynomial function with statistical value at an R2 of 0.9886, 0.9748, and 0.992, respectively. This research provides evidence that a relationship between muzzle-to-target distance and the concentration of metal on the target material not only exists but is a polynomial relationship. This relationship can be used to create mathematical models for varying metals in specific ammunition types and provides a quantitative method for distance determination in shooting cases.
Rights
© The Author(s)
Is Part Of
VCU Master of Science in Forensic Science Directed Research Projects
Date of Submission
4-30-2024