FORENSIC MINERALOGY: UTILIZING THE MINERALOGICAL, TEXTURAL, AND SPECTRAL PROPERTIES OF MAKEUP IN CRIMINAL INVESTIGATIONS

Abductions, human trafficking, and violence against women are cases of brutality that need to end, yet there are several challenges in the investigation and prosecution of these crimes. One proposed way of aiding associated criminal forensic investigation efforts is by linking the perpetrators with the victim through the application of spectroscopy to materials that remain at a crime scene. These analytical approaches are non-destructive techniques and allow rapid data analysis along with phase characterization in field and/or lab settings. In a multitude of cases, makeup is left behind as a residue on various different surfaces. Makeup itself consists of many industrial materials (such as talc and oxide pigments); these materials have distinct reflective spectra, allowing makeup to be utilized as potential evidence in a case. However, for this approach to be effective a spectral library needs to be developed for makeup and substrates on which it may be deposited. In order to develop a robust database, the investigation of spectral properties in a multitude of makeups while on various substrates under numerous conditions will be evaluated. Examples of makeup include foundation and eyeliner and examples of substrates where the victim would most likely leave behind a makeup residue include tile, carpet, wood, and concrete. The makeup, commonly worn by victims has the potential to be from a wide array of both high- and low-priced beauty retailers. The reflective spectra data of substrates, makeups and makeup on the substrates have been collected using an ASD spectroradiometer with an open path geometry. Preliminary work indicates 0.03 g/cm² of makeup can be detected under an open path geometry. The makeup and the substrates appear to have distinct spectra, even when the colors observed by the human eye are similar. By investigating the reflective spectroscopy of makeup and associated substrates, a new and versatile technique for collecting evidence is proposed as an aid to forensic investigations and in support of efforts to bring preparators of these crimes to justice.