During the investigation of a suspicious death, the determination of when the victim died is a critical piece of evidence. Estimating the amount of time that has passed since the person’s death, or post-mortem interval (PMI), can reveal this. This can be done in several ways, though in more advance stages of decomposition, this can be challenging. One way to do so when such obstacles are presented is through the study of the necrophagous insects colonizing the corpse. This includes blow flies in the early stages of decomposition, and progresses to beetles in advanced stages. The life cycle patterns of these insects are well-documented, this information can be used to work backward and estimate the time of death. Determining the species colonized on the body is often performed by collecting eggs, rearing them to adulthood, and then visually determining the species based on unique characteristics. This is not only time consuming, but requires the expertise of a trained entomologist. This is further problematic in the context of a forensic investigation, when time is often a precious resource. As such, there exists a need to develop techniques capable of determining PMI in an accurate and expeditious manner.

Our lab is currently investigating the use of mass spectrometric analysis to preform PMI determination. Each unique species is hypothesized as having a unique chemical profile. Building a database of these unique profiles would enable a rapid means for identifying the species of insect evidence, and the application of automated, statistical algorithms would eliminate the need for an entomologist to weigh in on the evidence. This can be accomplished using DART-HRMS, which represents a facile means for analysis of evidence in the form its typically collected from a scene. This work also has implications as a means of performing a toxicological analysis on bodies that are extremely deteriorated, as necrophagous insects feasting on the victim’s flesh may contain information about the drugs or medications in the person’s system at death.