New types of trace evidence are necessary to account for the potential lack of evidence found during criminal investigations, due to perpetrators' awareness of common types such as latent prints, hair, and DNA. During cases involving close personal contact, such as sexual assault, perpetrators may not be aware of the possible transfer of cosmetics from or onto the victim or crime scene. Therefore, this project focused on analyzing and developing characterization schemes for cosmetic components, specifically glitter and shimmer particles. Analysis of these particles was performed using various analytical techniques, such as microscopy and spectroscopy techniques, and the developed characterization models were cross-validated to ensure highly accurate performance. After developing characterization schemes, glitter, shimmer, and cosmetic products containing these glistening components were tested over time in different environmental conditions to determine effects on chemical profiles. The cosmetic transfer potential was also established by conducting skin-to-skin, skin-to-fabric, and fabric-to-skin simulations of close contact. Additionally, a human collection study was conducted where the amount of cosmetic residue remaining on individuals was determined after regular daily activities for up to 6 hours. Subsequently, to determine the optimal extraction procedure for analysis of cosmetic evidence, a method was developed to extract glitter and shimmer particles from cosmetic products without affecting their chemical profile or physical appearance. Then, extraction of glitter and shimmer from real-world cosmetic products was conducted on lipstick, eyeshadow, nail polish, lotion, bronzer, and highlighter. Extracted particles were tested against the developed characterization models to determine the ability to associate or discriminate true unknown, transferred glitter and shimmer samples collected from a suspect, victim, or crime scene. This thesis demonstrated the usefulness of these cosmetic components in enhancing the scope of forensic evidence analysis by providing yet another means to compare known and questioned samples that may have transferred during intimate contact.
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Doctor of Philosophy (Ph.D.)
College of Sciences
Length of Campus-only Access
Doctoral Dissertation (Open Access)
Najjar, Kandyss, "Identification and Detection of Cosmetics Transferred during Close Personal Attacks" (2021). Electronic Theses and Dissertations, 2020-. 1338.