Field Museum Botanist's Moss Analysis Helped Convict Burr Oak Cemetery Grave Robbers

A tiny clump of moss became crucial evidence that helped convict four employees in the notorious Burr Oak Cemetery grave robbing scandal, according to newly published research from Chicago’s Field Museum.

The crimes at the historic Alsip cemetery shocked the nation when they came to light in 2009. Employees had desecrated graves by removing human remains from burial sites, dumping them elsewhere, and reselling the plots, according to investigators.

Matt von Konrat, head of botany collections at the Field Museum, received an unexpected call from the FBI that year asking for help identifying plant specimens found with disturbed human remains.

“One day in 2009, I answered the phone, and it was the FBI, asking if I could help them identify some plants,” von Konrat said in the research paper.

The FBI handed von Konrat a moss specimen discovered embedded with human remains in a rear section of the cemetery. Investigators needed to know what species it was and how long it had been buried in the soil.

Von Konrat identified the moss as Fissidens taxifolius, commonly known as pocket moss, after comparing it with specimens in the Field’s herbarium and consulting international experts. The identification process revealed microscopic anatomical details that distinguish different moss species down to the cellular level.

A survey of the cemetery grounds showed a large colony of common pocket moss growing where graves had been disturbed, but no moss was present at the site where remains had been dumped and recovered, according to the research.

“So that gave us pretty strong evidence that the remains had come from this other section of the cemetery,” von Konrat said.

The botanical analysis addressed more than just the moss’s origin. Prosecutors needed to determine the specimen’s age to counter defendants’ claims that the crimes occurred before their employment at the cemetery began.

Scientists used moss’s unique metabolic properties to establish a timeline. Even when dry and dead, moss can maintain active metabolism in some cells, and this activity deteriorates over time, providing clues about when the specimen was collected.

Researchers tested chlorophyll amounts in the evidence specimen, fresh moss, and older moss from the Field’s collection. The complex analysis concluded the cemetery moss was only one to two years old, which aligned with the accused employees’ tenure at Burr Oak.

“Moss is a little bit freaky,” von Konrat said. “Even if they’re dry and dead and preserved, they can still have an active metabolism, a few cells that are still active. The amount of metabolic activity deteriorates over time, and that can tell us how long ago a moss sample was collected.”

The Burr Oak case marked the first time botanical evidence was submitted in an Illinois courtroom to establish a criminal timeline, according to the research. Four cemetery employees were ultimately convicted of desecration and other charges.

Von Konrat hopes the precedent will encourage law enforcement to consider botanical evidence in future investigations. He keeps a poster in his lab featuring FBI agents at the Burr Oak scene with the caption: “People lie, but moss does not.”

“Mosses are often overlooked,” he said. “We want to highlight this microscopic group of plants as a tool for law enforcement. If we can elevate mosses as potential evidence, maybe it could help some families somewhere in the future.”

The research demonstrates how scientific expertise from Chicago’s cultural institutions can support criminal investigations, providing forensic tools that help bring closure to affected families and ensure justice in complex cases.