Forensic Investigation of Bloodstains Using Raman Spectroscopy and Chemometrics: species differentiation, kinetic changes, donor age, and potential false positives

As submitted by the proposer: The field of forensic science is constantly growing so the advancement of old and unreliable techniques is at the forefront of what will lead to progress and improvement. Current methods for identification and analysis of bloodstains are underwhelming due to the insignificant amount of information provided in a destructive, unreliable, and unsafe manner. As is the purpose of this proposal, creating a new methodology that is rapid, non-destructive, robust, statistically reliable, and safe would significantly advance the way bloodstains are currently analyzed. The specific aims will be to determine the (i) time since deposition (TSD) and (ii) chronological age of a donor for bloodstains, and differentiate (ii) human from animal blood, and (iii) blood from potential false positive materials. This approach would provide immediate and lasting improvements to the theory and practice regarding serology as related to criminal justice.

A research-grade Raman microspectrophotometer, equipped with a 785 nm excitation laser and automatic mapping abilities, will be used to analyze samples for all proposed objectives. Blood from approximately 60 humans, varying in age, gender, and race/ethnicity, will be analyzed. Additionally, blood from about 10 animal species will be analyzed, using at least three donors each, from a wide selection of forensically-relevant species. Conventional spectral analysis will be used as well as multivariate statistics for building classification and regression models. For reliability, statistical levels of confidence will be assigned and all models will be internally and externally validated. All of the proposed work will be carried out in the Life Sciences Research Building on the University at Albany campus, over a two-year time period.

During the first year, kinetic changes of a bloodstain will be identified in ambient conditions and under different environmental conditions (i.e. high/low temperature and humidity). Spectra will initially be confirmed as human blood and, subsequently, the TSD will be estimated. In an effort to comply with a more practical application, analysis will be completed using a hand-held Raman instrument during the second year. Separately, methodology will be developed to accurately estimate the chronological age of the donor.

The work being described here will benefit from a partnership with the Department of the Army, Defense Forensic Science Center (DFSC); specifically with their pending financial support to purchase a portable hand-held Raman spectrometer if the fellowship is awarded. The DFSC and the NIJ will be kept abreast of all progress through written reports and data archiving.

This project contains a research and/or development component, as defined in applicable law. nca/ncf.