Kevin Neal, Convicted of Murder by Forensic Entomology
Messages from the Dead
As anyone who has ever attended a picnic on a warm summer afternoon can attest, insects, particularly flies, have an almost uncanny ability to show up whenever food is around. As we watch these arthropods buzz from potato salad to Jello to the plate that once held a hot dog, if we think about it at all, we probably assume that these unwelcome guests are looking for food. This assumption is only partly correct. While adult female flies do feed, their primary objective, programmed into their genetic make-up, is to find the proper environment to propagate their species. When flies crash our picnics, they come in search of carrion — dead, decaying flesh — in which to lay their eggs.
Insects are creatures of rigid habit and limited preferences. They are very specific about when and where they will lay their eggs, and the larvae that emerge and mature from those eggs do so according to well-documented rules. Because of the regularity and measurability of an insect life cycle, when forensic entomologists — scientists who use insects to help solve crimes — can control for other variables like weather, moisture, and clothing, they can use the information left behind by bugs to provide police with guidance about time of death, whether a body was moved, and other essentials. Forensic entomology requires its experts to make qualified "guesses" based on circumstances, but more often than not, a careful reading of the signs left behind by bugs can help catch a killer.
The idea of using insect activity as a means to catch criminals is not new. In the Yuan Dynasty (around 1300 A.D.), a Chinese mandarin named Sung T'zu made the first recorded observations of the usefulness of insects in solving crimes. Sung, who was responsible for investigating mysterious deaths for his emperor, wrote in one of the earliest criminology works, poetically entitled Washing Away of Wrongs, that "during the hot months, if maggots have not yet appeared at the nine orifices [of the body], but they have appeared at the temples, hairline, rib cage, or belly, then these parts have been injured."