Gunshot residue (GSR) is important evidence that can place a person at the scene of a crime with the smoking gun—literally—or prove someone’s innocence. Some questions, however, can completely undermine the results of GSR tests.
At Duquesne, Dr. Stephanie Wetzel is conducting research to determine the answer to one of the most often asked GSR questions—with regards to secondary transfer, could the GSR have gotten on a suspect’s hands by means other than actually firing or being in the vicinity of a fired gun? An assistant professor of chemistry and biochemistry in the Bayer School of Natural and Environmental Sciences, Wetzel and her team of student researchers have focused on GSR transfer from police officers, police vehicles and stations.
As part of the research, student volunteers were handcuffed, placed in a police car and then tested to determine whether any GSR had been transferred onto them. The team used two methods of GSR detection. SEM-EDS is used to identify characteristic primer residues, which include barium, lead and antimony. LC-MS/MS is used to identify organic gunpowder residues.
Wetzel’s work has shown that while GSR transfer is possible, it is minute in these scenarios. The research also indicated that it is possible to extract and detect GSR after an aluminum carbon-coated adhesive pad has been analyzed using the SEM/EDS detection method. This finding, Wetzel said, opens new doors for the future of GSR testing because analysts will be able to test the same sample using both the SEM/EDS and LC-MS/MS methods.
“It is important to understand GSR and its transfer to acquire accurate information from a crime scene and suspects,” said Wetzel.
Wetzel and her research team are currently conducting a number of other GSR-related studies, including:
- Transfer during handcuffing by a police officer who has just discharged a firearm
- Home loaded ammunition and variations in gunpowder GSR
- Handshake transfer
- How fast GSR settles to the ground once a weapon has been fired.
Wetzel’s current findings will be published in the September edition of the Journal of Forensic Sciences in an article titled A Study of the Presence of Gunshot Residue in Pittsburgh Police Stations using SEM-EDS and LC-MS/MS.
Grants Received [April 19, 2017]
Funds totaling $8,000 were recently received by the School of Education and the School of Pharmacy.
DU in the News [April 2017]
News coverage highlighting Duquesne’s experts and initiatives.
Grants Received [April 12, 2017]
Funds totaling $53,500 were recently received by the School of Law.
- Grants Received [April 19, 2017]
Spring Clean-Up: More Than Picking Up Litter and Planting
The 27th annual Spring Clean-Up is a one-day, large-scale litter pick-up and greening event that takes place throughout the South Side and Greater Hill District neighborhoods; however, it is much more than that.
- Spring Clean-Up: More Than Picking Up Litter and Planting