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A bloodhound bays as it picks up the trail of a suspected criminal in the woods. 

Police find the weapon used in a nearby robbery — a shiny, hard, plastic firearm. 

These two crime scenarios share one crucial similarity: both represent legal gray-ares for law enforcement, as the science behind scent and 3D printed firearm identification is not well understood or studied. No one can definitively explain the process by which a dog can make a scent connection to an individual, and 3D printed material cannot as of yet be tied to specific source products. This means that a dog ID of a suspect, or an accused person having a 3D printer in their basement with a spool of plastic in the same color as the gun, are both circumstantial in the extreme. 

A dedicated team of Oles are trying to change that. 

Through the Collaborative Undergraduate Research and Inquiry (CURI) program and under the mentorship of Professor of Chemistry Douglas Beussman ‘92, a pair of students are exploring two highly specialized areas: human scent analysis and isotope ratio analysis of 3D-printed materials. 

Beussman’s research uses advanced instrumentation — specifically, mass spectrometry — to answer questions with real-world applications. 

“When I came to St. Olaf, I wanted a research program that undergraduates could do and be excited about,” he says. “Developing a forensics program felt like a natural draw for students.” 

One of Beussman’s long-running projects investigates whether every person has a unique scent signature — something so distinct that, one day, it could be used as identifying evidence. The work stems from his sabbatical collaborations with the FBI, where he studied how trained dogs can follow a single individual’s trail through crowded environments. Under current federal laws, dog identification via scent is not admissible in court, as the process by which the dog made that determination cannot be replicated by a secondary process.

“You can’t really ask a dog how it’s following one person’s trail versus another, but these trained dogs can literally follow one person’s trail amongst hundreds,” Beussman says. “For example, I could walk around campus on a Monday, and on Tuesday come back to the dog, take a gauze pad, rub it on my hands, shove it under the dog’s nose, and the dog would follow my trail, ignoring the other 3,000 students and staff walking around campus. If that’s true, it means everybody must have a unique scent.”

To study that, Beussman’s lab collects volunteers’ skin-cell samples, seals them in vials, and analyzes the trace chemicals that emerge over time. The team has already found evidence of distinct individual profiles and is now investigating whether the scent can reveal factors like age or ethnicity. Early data suggests that one compound may distinguish between minors and adults — potentially offering new tools for forensics if validated in future studies. 

For Tine Museba ‘28, a rising sophomore student from Gweru, Zimbabwe, joining the project was a chance to explore chemistry for the first time. 

“The most rewarding part of the summer was getting to explore analytical chemistry research, because I’ve never done it before, but I loved the idea that this research connects to real forensic science,” she says. “I collected skin-cell samples from people of different ages and ethnicities, then analyzed them to see what compounds were present.”

Museba’s work contributes to a growing database aimed at proving the uniqueness of scent across hundreds of samples. She says the most challenging part was recruiting participants across age groups (not many toddlers on a college campus!), but the experience gave her a new perspective on science. 

“With this type of research, you get to have more direct mentorship, and you direct your own pace and process — you get to think, problem-solve, and analyze your own work.”

Tine Museba ’28

“Research is way different than what we do in classes and labs, because that work is so academic, and this was more active,” Museba says. “With this type of research, you get to have more direct mentorship, and you direct your own pace and process — you get to think, problem-solve, and analyze your own work.”

Another student in Beussman’s lab, Eliza Champion ‘27 of Champaign, Illinois, spent the summer studying the isotopic forensic fingerprints of 3D-printed plastics — a growing area of concern for forensic investigators as so-called “ghost guns” become more common. 

“There are more 3D-printed weapons being confiscated every year,” Beussman says. “There are places on the web — and I do not recommend you search for them, because it will put you on a list — where you can download plans to print a handgun on a 3D printer. The scariest thing is it doesn’t have a serial number, so it’s not traceable. To my knowledge, there hasn’t yet been a fatality linked to a 3D-printed handgun, but it’s a matter of time. Our goal is to be ahead of that curve.”

Champion’s project analyzed the isotope ratios of carbon in PLA (a common printing material) to determine whether different brands can be distinguished, and whether printing alters those signatures. 

“Because these weapons are made out of plastic, they aren’t detected by metal detectors, and so right now if we found a ghost gun, all we can really say is it was printed out of whatever kind of plastic,” Champion explains. “We may have a suspect who has a 3D printer in their basement, but there is no way to connect the gun to the suspect. We’re hoping to figure out a way to connect the material to an individual spool of plastic, that could then be circumstantial evidence in court. I’m comparing something like ‘blue’ from company A to ‘blue’ from company B and hoping that there are distinct differences, and we also have to be able to say that ‘blue’ from company A hasn’t changed in the printing process from it was before.”

Her process was both meticulous and technical: preparing microplastic samples, feeding them through an elemental analyzer and an isotope ratio mass spectrometer, and processing hours of data. 

“I was kind of beholden to my machines all summer,” Champion says. “I wasn’t doing all that much besides making samples and looking at numbers. A full run takes about eight hours, so getting clean, consistent data is incredibly rewarding.”

By the end of summer, she had produced over a thousand samples — including standards — and gathered evidence suggesting that filaments from different manufacturers can indeed be distinguished. Champion continued the project this semester, with the goal of presenting at a national conference and eventually publishing the findings. 

“This summer gave me more confidence in the lab and helped me see what research is really like,” she says. 

Beussman says one of the most rewarding aspects of mentoring CURI students is watching them transition from structured coursework to independent inquiry. 

“Until they do research, most students don’t necessarily have a great concept of what research is about,” Beussman says. “They’ve taken labs as part of their coursework, but those labs are designed to work. If you do all the steps correctly, 95 percent of the time, you should get the right result. Research isn’t that way, because we haven’t done it before. Sometimes things fail even when you do everything correctly. The key is learning from what didn’t work and pivoting.” 

This summer’s group included many first-year and sophomore students, which initially made Beussman cautious. By the end of the program, he was impressed. 

“The biggest reward is when a project stops being my project and becomes their project. When they’re texting me at 8 p.m. with ideas for the next morning, you know it’s clicked.”

Professor of Chemistry Douglas Buessman ’92

“The biggest reward is when a project stops being my project and becomes their project,” he says.”When they’re texting me at 8 p.m. with ideas for the next morning, you know it’s clicked.”

Both Museba and Champion say that independence was central to their experience. 

“I liked being able to make decisions and troubleshoot on my own,” Champion says. “I’ve gotten better with being alone with myself for long swaths of time, and getting a little bit more confident being in a wet lab without someone to refer to all the time.” 

“You learn time management, communication, and confidence,” Museba adds. “It showed me what real research feels like.”

Both projects have continued into the academic year and will likely extend beyond, building larger datasets and refining techniques. Beussman emphasizes that this work — and the student opportunities it creates — wouldn’t be possible without external support. 

“Both of these projects have been funded at least in part by donations to the college. That support makes a bigger impact than many people realize: it helps students figure out what they love, or sometimes that research isn’t for them — which is just as valuable.”