A team of pathologists has published a paper revealing how, for the first time, crime investigators identified the body of a burn victim by conducting a DNA analysis of the gastrointestinal contents of the maggots feeding on the remains.

The revelatory study, published in the Journal of Forensic Sciences, cites the case of an unidentifiable body found in the woods by Mexican police. It was suspected the body was that of a woman who had been abducted ten weeks earlier—her graduation ring was found near to the scene, however, the body was burned so badly it was impossible to collect any DNA samples from the damaged and deteriorated tissue.

It had already been suggested by other researchers that the gastrointestinal contents of maggots could be used to identify the subjects they feed on. However, never before has the theory been trialed in a legal, criminal case. Pathologists at Autonomous University of Nuevo León in San Nicolás, Mexico, led by María de Lourdes Chávez-Briones and Marta Ortega-Martínez, carried out short tandem repeat typing tests (a common method of DNA profiling) on the matter extracted from three dissected maggots found on the victim's face and neck, and separately on the alleged father of the missing woman. Preliminary results showed that the body was female, and the final outcome was a 99.685 percent probability of positive paternity—the victim had been identified.

Speaking to the New Scientist, Jeffrey Wells, a biologist at Florida International University who specializes in genotyping and insect evolution in relation to forensics, explained that the method could have plenty of practical applications, including identifying a victim through analysis of a maggot found in a vehicle transporting a body.

Maggots are already commonly used in criminal investigations to help police calculate time of death, particularly in bodies left to decompose for more than 72 hours. This is done by identifying the species of maggot infesting the corpse and working out how long that species has been alive by measuring it—shortly after death, blowflies and flesh flies are attracted to the body and lay larvae, which become maggots. By taking the maggots back to the lab and letting them grow to adulthood, thus ensuring the species has been correctly identified, police can get a pretty accurate timeline of events. One etymologist is even setting up a DNA sequence database so maggot species can be detected earlier.

Investigators are now catching up with research that has been ongoing in this area for some time now, recognizing the other potential practical benefits provided by corpse-loving insects. Pathologists are, for instance, also keen to use DNA extracted from hematophagous arthropods (blood-feeding insects) to identify corpses. In one study, adult crab lice removed from volunteers were frozen, air-dried and then profiled using the same methods designed for extracting mitochondrial DNA from human hair, teeth and bone. A comparison with DNA extracted from the volunteers' saliva showed the method could work in real-world cases, such as the one in Mexico. It can even be done with bed bugs. The stomach-churning possibilities of this burgeoning field seem to be wide open, and heralding in a new age of insect-aided criminal investigation.

Listing image by Pieter Cornelissen