Halloween Special: An Analysis of Blood Spatter from a Chainsaw

Here's a shocker: Horror films like Texas Chainsaw Massacre don't get the chainsaw spatter right, according to the Journal of Forensic Sciences.

The reason for the study is sad—a woman was reported missing in 2005, and the police found evidence that she had been killed and dismembered in her basement (a few dabs of fresh paint on the walls, small pieces of bone, a receipt for an electric chainsaw). The investigators, possibly having watched a few too many horror films, didn't think that there was enough blood and tissue spatter in the small room if a human body had been dismembered there by someone wielding a small chainsaw. And there was the question of whether or not the chainsaw itself was powerful enough to accomplish the job without getting stuck in flesh and bone.

A University of South Dakota pathologist got involved. He obtained the same kind of chainsaw indicated in the receipt and a 200-pound female pig, deceased, and created a room the approximate size of the basement using white sheets. He let the pig rest for two days to simulate the time between when the woman had been reported missing and when the chainsaw was purchased. And then he started hacking away.

The chainsaw was certainly powerful enough to cut through the tissue and bone. And the pathologist discovered that if the blade was held parallel to the floor there was very little spatter, similar to what was found at the crime scene. (Vertical positioning of the blade or use of a freshly killed pig increased the amount of spatter on the sheets.) The researcher concluded:

These experiments have shown that a human body may be easily dismembered with a chainsaw, even a smaller electric-powered model....Despite popular beliefs fueled by crime scene shows on television and recent Chainsaw Massacre movies, postmortem dismemberment does not necessarily produce a large amount of blood spatter at a dismemberment scene....With a horizontally oriented chainsaw, therefore, the majority of the tissue and blood will be found on the ground beneath the saw. If the chainsaw discharge chute, however, is not directed towards the ground, then a large volume of blood and tissue, and subsequent spatter, could be expected some distance from the saw.

Something to consider when writing or filming your next scary movie.

Sarah Zielinski | | READ MORE

Sarah Zielinski is an award-winning science writer and editor. She is a contributing writer in science for Smithsonian.com and blogs at Wild Things, which appears on Science News.