My research is primarily geared toward the disciplines that the forensic science community defines as trace evidence and questioned documents. Trace evidence, or perhaps better termed as (trace) materials, encompasses different types of ubiquitous substances (mass produced or widely occurring in nature). Following the classic view, the most commonly encountered types of materials are fire debris, gunshot residue, hair, textile fibers, paint, tape, and glass. A lot of my research involves substances that contain colorants (i.e., dyes and pigments). Questioned documents is a forensic discipline where examinations of any type of document suspected to be altered, forged, or counterfeited can involve a large array of activities, such as the comparison of handwriting and signatures, the identification of printing devices, the use of filtered lights or radiations, or the analysis of inks, toners, or paper, and much more.
My approach to research involves the integration of the following elements
- Chemical analyses
- Data analysis or probabilistic reasoning
Investigation of a time-effective approach to the discrimination and interpretation of inkjet printer inks using micro Raman spectroscopy to produce investigative leads
This collaborative project with the Forensic Counterfeit Unit of the US Secret Service intended to evaluate if Raman spectroscopy is a suitable method to obtain chemical signatures from inkjet printed documents able to provide reliable investigative leads in a time-effective and non-destructive manner. In this project different chemometric approaches were evaluated and compared with the classic approach of comparing data visually and also with the routine method of ink analysis of thin layer chromatography.
The Effect of Ultraviolet Radiation on the Microspectrophotometry (MSP) of Dyed Textile Fibers
This project in collaboration with the renowned McCrone Research Institute in Chicago aims providing information useful to the interpretation of MSP data in typical casework when unknown fiber specimens and reference fiber samples are collected at different times. A large variety of man-made commercial and man-made custom-dyed fibers were exposed to natural and UV radiation in a laboratory setting and measured using UV-Vis MSP at intervals of 10 weeks over a period of 18 months.
Development of a baseline survey of random presence of glass and paint for the interpretation of evidence in the US Courts
This collaborative project with Dr. Tatiana Trejos at West Virginia University aims providing background knowledge on how unlikely it would be to recover by chance glass and paint particles on individuals. Information from this study will be helpful to the interpretation of trace evidence when addressing questions about activities rather than sources.
Evaluation of data fusion from spectroscopic techniques to the maximization of the efficiency of the analytical sequence for paint examinations (Morgan Carpenter, doctoral research)
This project intends to combine data from different techniques that paint analysts routinely use; since most methods produce data that are redundant, the idea is to sort the most variable features of paint specimens to be considered for comparative examinations and subsequent interpretation.