Some bodies arrive already infested, which his beautiful slides graphically showed, and he takes the critters of those corpses as well. When he determines the species, he can begin to hypothesize about different aspects of the death of the person. From the length of the maggots, they can determine the developmental stage of the creatures, which can show how long the insects have been feasting off the corpse. Temperature data can be crucial for certain cases because maggots grow at an increased rate with higher temperatures. He can also determine if a corpse has been moved due to the ecological properties of maggots.
Some bugs live in a particular climate and in that climate only.
If a murderer moves a body, Dr. Benecke will know because the corpse may contain maggots found in the particular area of the murder, not in the area of discovery. All these methods help him and his colleagues help the district attorney gather evidence about cases involving death, and they provide information about death in general. The first murder case in history solved with the help of insects occurred on a rice field in China. Except for the flies. Though the blade was clean to the human eye, the flies were attracted to the blade that had the scent of blood.