How a piece of moss helped catch a gang of grave robbers

The age of the moss proved to be crucial evidence in convicting four cemetery workers who were carrying out illegal exhumations to resell the burial spaces.

A small fragment of moss proved decisive in condemn four employees of a cemetery in the United States for a macabre grave-robbing scheme, according to one published in the journal Forensic Sciences Research.

The case dates back to 2009, at Burr Oak Cemetery, on the outskirts of Chicago, where authorities discovered a illegal body exhumation scheme. Cemetery workers are accused of digging up bodies, moving the remains to other areas and reselling the burial spaces. Investigations indicated that around 1,500 bones, belonging to at least 29 individuals, were removed and reburied in a different area of ​​the land.

One of the key elements of the investigation came when the FBI requested the help of botanist Matt von Konrat of the Field Museum. The agents had found a small tuft of buried moss about 20 centimeters deep, next to human remains suspected of having been displaced.

The analysis identified the plant as common moss (Fissidens taxifolius), a species that did not grow in the area where the bones were foundbut which existed in another area of ​​the cemetery, precisely where investigators suspected the bodies had originally been buried. This discovery helped establish a link between the exhumation and reburial sites.

However, it was determining when the moss was displaced that proved crucial. Using techniques to analyze the degradation of chlorophyll, the pigment responsible for photosynthesis, scientists were able to estimate the age of moss. As chlorophyll deteriorates over time, measuring its activity led to the conclusion that the material was only one to two years old.

This data directly contradicted the defense of the accused, who claimed that the crimes had occurred before they started working at the cemetery. Based on this and other evidence, the four employees were convicted in 2015 of desecration of human remains, writes .

According to researchers, the use of mosses and other plants as forensic evidence is rare, having been identified in only about a dozen cases over the last century. Still, the study highlights the potential of this biological evidence in criminal investigations, suggesting that it may be more valued in the future.