Date of Award

Fall 12-2020

Document Type

Thesis

Degree Name

Master of Science (MS)

Department/Program

Forensic Science

Language

English

First Advisor

Peter Diaczuk

Second Reader

Patrick Mclaughlin

Third Advisor

Andrew Winter

Abstract

Determining the muzzle to target distance of a firearm discharge is an integral part in crime scene reconstruction. Shooter distance is most often estimated using the Modified Griess test, which can be used to visualize gunshot residue (GSR) patterns around bullet holes. However, this test has a 3- to 5-feet range limit as the plume of GSR particles can only travel a certain distance past the muzzle. The purpose in this study was to develop a new method that overcomes this range limitation by analyzing the physical damage characteristics of a bullet hole. Test fires were conducted with a .22 caliber rifle over a range of muzzle to target distances and different bullet velocities. The goal of the study was to simulate an indoor shooting on plywood and Medium Density Fiberboard (MDF) panels. The results show that as muzzle to target distance increases, bullet hole depth decreases. In addition, specific damage patterns were observed on the back of the substrates relating to shooter distance and bullet velocity. A predictions model was developed using this data that allowed shooter distance to be estimated based on bullet hole depth. Conclusions were made that not only does this new method cover the limitations of the Modified Griess test, but it also works in tandem with other ballistics analysis methods. With some finetuning, this method may be of use to forensic scientists in casework.

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