Moss helped nab notorious grave-robbers

It may still lie beneath our feet, but moss has been closely linked to human history for thousands of years. Native cultures often harvested the plants as bedding material and structural insulation. Europe’s oldest natural mummy, Ötzi the Iceman, died with moss in his boots to keep him warm. Meanwhile, Scotch whiskey wouldn’t even exist without the degrading power of peat – a terrifying thought, if ever there was one.

More recently, botanists have begun to emphasize one of the plant’s most underutilized uses: its ability to solve crimes. Let’s take the case presented in a study published today in the journal Forensic science research. According to botanists at Chicago’s Field Museum, the moss helped bring closure to a 17-year-old grave robbing case that rocked the town of Alsip, Illinois.

In 2009, Burr Oak Cemetery employees were accused of digging up old graves, dumping their remains in various locations around the grounds, and then reselling the burial plots to new grieving families. National attention quickly followed news of the crime. Burr Oak, a historic black cemetery, includes the graves of civil rights figure Emmett Till, blues musician Willie Dixon and first lady Michelle Obama’s father, Fraser Robinson. During the ensuing investigation, FBI agents sought help from Matt von Konrat, manager of the Field Museum’s botanical collections.

“Investigators wanted to know what type of moss it was and how long it had been buried in the ground,” von Konrat said in a statement.

The moss in question was found about eight inches below the topsoil, near some human remains reburied in the cemetery. Specifically, the FBI needed to know the exact species of moss, its age, and where it grew in the cemetery. It was quite easy to identify the species because Fissidens taxifoliusor common pocket foam. The rest of the information required a field trip to Burr Oak Cemetery.

“We studied the different types of moss growing near the crime scene, and this species of moss did not grow there,” von Konrat said. “When I inspected the rest of the cemetery, we found a huge colony of this moss species growing in the same area where the investigator suspected the bones had been dug up.”

The age of the sample was also extremely important. The defendants said other workers likely committed the crimes before they began working at the cemetery. Given that the moss was found alongside the disturbed remains, it stood to reason that its age would help clarify the overall timeline. Fortunately for investigators, the plant has some truly frightening attributes.

“Moss is a bit weird,” von Konrat said. “Mosses have an interesting physiology, where even though they are dry and dead and preserved, they can still have an active metabolism, some cells still active.”

Similar to radiocarbon dating of fossils, the level of metabolic deterioration in moss can tell botanists when the plant was harvested or moved. To analyze this, von Konrat’s team compared the amount of chlorophyll in the sample with various museum specimens collected at different ages. They then concluded that the cemetery evidence was only a year or two old and had definitely been reburied during the accused employees’ tenure at the cemetery. Thanks to this small clump of moss, the defendants were ultimately convicted of desecration of human remains in 2015.

This isn’t the first time von Konrat has touted foam’s crime-fighting capabilities. Last year, his team published a review of 150 years of cases around the world in which Moss helped bring the guilty to justice.

“Mosses are often overlooked and we hope that our research will help raise awareness that there are other groups of plants, apart from flowering plants, and that they play a very important role in society and around us,” von Konrat said.

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