The smell of death: Characterization and Applications

After death, a body undergoes a complex decomposition process during which hundreds of volatile organic compounds (VOCs) are released into the surrounding environment. By exposing pig carcasses to decomposition in forests, meadows, and indoor settings, we revealed the strong influence of the environment on the cadaveric odor profile. We also demonstrated that the colonization of corpses by necrophagous insects not only accelerates decomposition but significantly alters the VOC composition. These insects possess specialized olfactory sensilla that enable them to perceive decomposition-derived chemicals and use them as cues to locate and colonize fresh cadavers. Remarkably, the parasitoids of these scavenging species exploit the same chemical signals. We further characterized the VOCs emitted by submerged and buried remains, as well as those present in soil layers located above and below buried rat carcasses. Since studies examining the odor of human corpses remain scarce and constrained by small sample sizes, we undertook a comprehensive characterization of the human cadaveric volatilome through periodic visits to a morgue. Using dynamic headspace collection, we collected the VOCs released by 20 human corpses at the fresh stage, and we assessed the influence of skin temperature, sex, age, body size and postmortem interval on the volatilome.
These findings have led to a collaboration with Belgian federal police officers specializing in the search for human remains. Through a series of behavioral assays, we demonstrated that human remains detection dogs responded positively to a simplified synthetic blend composed of the principal cadaveric molecules. Notably, we showed that these dogs do not target specific cadaveric compounds but rather respond to broader chemical families and are capable of detecting cadaveric cues at concentrations as low as 100 nanograms. This simplified blend is now used by dog handlers for the routine training of their animals.