Syracuse’s all too familiar snowy winters are no match for the staying power of fingerprints, recent research shows. While quality declined over time, fingerprints placed on soda cans and then exposed to snow for multiple weeks could still be processed by forensic methods. The results suggest that non-porous items found at crime scenes can yield forensic clues, even if they’ve been exposed to inclement weather.

“A review of the literature showed that little to no research had been done on this topic. Given that Syracuse gets plenty of snow, I thought this would be a new and interesting avenue to investigate,” says Sam McCook M.S. ’15, a former Forensic and National Security Sciences Institute (FNSSI) student and the study’s lead author.

The study, published in Volume 66, Issue 6 of the Journal of Forensic Identification, grew out of an assignment in the FNSSI course: Advanced Latent Prints. The course, taught by study coauthors and Onondaga County Center for Forensic Sciences latent print examiners David Tate and Jesse Eller, required students to design a research project related to fingerprints found at crime scenes, also known as latent prints.

“Sam had an idea that was sound and had a practical application,” Tate says. “He was also an excellent student, very ambitious. Jesse and I suggested that if he was interested, he could do more elaborate research with the intent of publishing his project. And so he did.”

Many objects may be recovered from any one crime scene, leaving forensic analysts with mountains of objects that may contain identifying evidence, or may be dead ends. “With evidence recovered from crime scenes we’re working backwards. We don’t know whether or not someone has recently handled it or how they handled it, how long it’s been at the scene, what conditions were,” Tate says.

The latent print examiner’s challenge is to most efficiently use time and resources, he says. Studies like McCook’s can guide forensic offices in what sort of recovered items are worth processing for latent prints.

In the study, McCook placed fingerprints on non-porous soda cans and exposed the printed cans to different snowy conditions for 1 to 50 days. After the cans were retrieved, they were processed with ethyl cyanoacrylate fuming and various dyes to reveal friction ridge detail, all common methods used in forensics labs. Latent prints were recorded with photo-capture equipment in the Onondaga County Center for Forensic Sciences.

While the researchers found that print quality deteriorated over time, ridge detail of all 167 prints left on cans was recovered. And the study’s results extend beyond soda cans, Tate says, since all non-porous objects require the same latent print processing, including the most commonly recovered pieces of evidence: guns, knives and drug packaging.

As for McCook, he is living in Georgia and working on joining the Atlanta Police Department Crime Laboratory as a latent print examiner. But he continues to sing the praises of FNSSI—particularly the basic and advanced latent print courses: “I would strongly recommend taking the latent print courses that FNSSI offers. Both Dave and Jesse are great instructors and are able to provide an academic perspective on the discipline, which is uniquely coupled with real-world knowledge.”