A professor at Des Moines University is conducting a national research project that at first glance seems like a segment of This Old House. Anatomy professor Heather Garvin is studying the cutting characteristics of saws, but her focus is how the saws cut through human bones, not wood.
“And the reason we’re looking at this is that we do get cases of dismemberment in the forensic anthropology, world,” she says. “And what we try to do for law enforcement and for investigators, is to give them as much information as we can about the tool that was used.” Garvin is the only board certified forensic anthropologist in the state of Iowa and one of only about 120 of us throughout the country.
Garvin says the work focuses on identifying the type of saw used in a crime to help investigators. “We can’t say that it is this one specific saw, the saw that was used, but we can say what type of saw and the characteristics of a saw,” Garvin says. “So for example, powered saws will leave lighter, wider cuts in the bone than hand saws.” Garvin says they can’t be like ballistic experts who can link a bullet to the specific gun it was fired from, but they hope to identify different marks left by the teeth of saw blades. “If anyone works in carpentry, they’ll realize there’s there’s a large variation of saws out there where you have different teeth per inch different size teeth, different materials, whether they’re cutting like a knife, or if they’re ripping through the material,” Garvin says. “And so we’re trying to figure out what characteristics those marks in the bone correlate with.” She says other individuals in the project will be collecting data blindly so they won’t know what saws made the cuts and they can do a statistical analyses to see if they can use the marks on the bone to identify the type of saw.
Garvin says dismembering a corpse after a murder isn’t something that’s all that common in Iowa. “But in other areas of the country where you have very urban areas and it’s harder to dispose of a body during a criminal act, you do get a higher number of dismemberments, because that makes it easier for them to hide and then dispose of human remains,” she says. Garvin won a grant from the National Institute of Justice to do the saw research. She says they use a microscope with a camera to study the cut marks, and may eventually use micro CT scan that can put together x-rays in a sort of 3D model. “It’s a little harder with cut marks, because what we’re dealing with really doesn’t have much relief. You know, these are tiny scratches in the bone that we’re looking at,” Garvin says. “But I think as technology advances and it becomes more sensitive with that micro CT, that might be an avenue as well.”
It might seem kind of gruesome to do this research on human bones, but Garvin says she can block that out and see it as important scientific work. “The thing is, someone has to do it and by doing it, you’re helping loved ones have a family member right? They may have a missing family member, they don’t know where they are, you’re able to identify those remains and bring some closure to that family,” Garvin says. She says it can also help with providing the evidence that brings justice for the person who was killed.