Presumptive Screening of Physical Evidence
Original Event Date: Tuesday, April 30, 2013
Duration: 60 minutes
Presenters: David Exline, Senior V.P. & Court-Qualified Trace Evidence Expert & Cara Plese, M.S., Scientist I at Gateway Analytical
Host: Shawn Wilhelm, Marketing Coordinator at Gateway Analytical
Highlighted Topics Covered:
- The advantages of microscopic and presumptive screening of physical evidence prior to expensive DNA analysis
- How these screening methods can save time, money and resources by potentially eliminating unnecessary further analysis
- The importance of proper packaging of evidence collected at the scene to ensure it is not compromised prior to analysis
Webinar Overview:
Presumptive tests for blood, seminal fluid, urine, and saliva are fast, relatively inexpensive, and can quickly eliminate a stain from further analysis if the results show the sample is not the fluid originally suspected. Likewise, microscopic analysis of hair is a nondestructive test involving minimal preparation and can confirm if hair is human in origin and determine if a particular hair is suitable for nuclear DNA analysis. Both time and money can be saved by efficiently eliminating samples from further analysis when it is deemed unnecessary by a presumptive method. This webinar was designed for police and attorneys involved in cases with physical evidence. During this webinar, our presenters discussed the advantages of microscopic and presumptive screenings of physical evidence, especially suspected bodily fluid stains and hair prior to advancing to more expensive DNA analysis. They also provide examples of such screenings and discussed how these screening methods can save valuable time, money and resources by eliminating samples from being forwarded onto unnecessary further analysis.
Presenter Bios
David Exline
David Exline, Senior V.P. & Court-Qualified Trace Evidence Expert Gateway Analytical David is a court-qualified expert in the area of trace evidence examination and has instructed law enforcement agencies, attorneys and students in the collection, preservation and examination of various types of trace evidence, including hairs, fibers, paints and gunshot residue. David earned his MSFS in Forensic Science from the University of Alabama Birmingham, and has more than 18 years of experience in specialized trace evidence examination, including cold case review, accident investigation, industrial and pharmaceutical forensics.
Cara Plese
Cara Plese, M.S., Scientist I Gateway Analytical Cara is experienced in performing analytical laboratory work, specifically performing characterizations of unknown materials, in both the pharmaceutical forensic and criminal forensic fields. She was trained and performs investigations in a quality-oriented environment, including both ISO and ASCLD/LAB accreditations. Cara has previously presented research at the MAAFS annual meetings and has publications in The Journal of Forensic Identification and The Journal of Forensic Sciences.