Three to four days after death, coroners can no longer determine the exact time of death using classic properties such as body temperature, post-mortem lividity, changes to the pupils, muscular twitching or rigor mortis. Enter the forensic entomologists. Their task is to examine the corpse and its vicinity for the presence of insects. Arthropods are often silent witnesses of a crime and provide information that has destroyed many an alibi. Flies lay their eggs on corpses within 15 min of the last breath. Larvae hatch from the eggs, and flies emerge from the pupae. Forensic biologists can determine the time of death of a corpse with great accuracy on the basis of these stages of development.