Date of Award

Summer 8-2017

Document Type

Thesis

Degree Name

Master of Science (MS)

Department/Program

Forensic Science

Language

English

First Advisor

Mechthild Prinz

Second Reader

Lawrence Kobilinsky

Third Advisor

Zhe Cheng

Abstract

Cartridges and spent cartridge casings can be probative pieces of evidence. Unfortunately due to a combination of factors such as exposure to high temperatures and initially low amounts of biological material on the surface, DNA testing so far has been mostly unsuccessful for these items. Typing other marker systems, such as protein polymorphisms, on the same biological evidence would add power of discrimination. To explore this option we developed a DNA-protein trypsin-based co-extraction method that was optimized for unfired and fired cartridges. Various sample wet and dry collection methods and multiple metal casings, such as aluminum, nickel, steel, and brass were tested. Tape lifting with the Voigtlaender Neschen Foil S23 was determined to be the best sample collection method. Cartridges with brass casings were determined to yield the least amount of DNA and protein. For most metals fired cartridge casings yielded less biological material than unfired cartridges, but this finding was only significant for steel (protein), and steel and aluminum (DNA). Many touched cartridge casings negative for DNA were positive for identifiable protein fragments. But ammunition straight out of the box and even some substrate control samples collected from cleaned casings also yielded peptide signals. Therefore further testing evaluating environmental levels of protein will be necessary.

Available for download on Thursday, February 14, 2019

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