Crime scene investigators are learning all kinds of new tricks to catch criminals and in this article we’d like to share some of the methods they use to solve crimes with insects.
Let’s say a person is lying dead in a thick wooded area. If the investigator sees a slew of blue-green looking flies on the body, he knows that they are always first on the scene. These flies usually arrive within five to ten minutes and can smell death from ten miles away.
The insect population on the body will change as minutes turn to hours, turn to days and then to weeks and months. Flies, beetles and mites will come and go. The type of insect found is dependent on surrounding conditions, including temperature and climate. Some types of insects will feed on the corpse, and others come to lay eggs which will hatch and later become larvae.
When a suspicious death occurs, investigators can examine insect activity on the corpse and use it to determine post mortem interval (PMI). PMI is the estimated time that has elapsed since a person has died.
Insect samples from the crime scene are collected and taken to a lab for further examination. PMI is determined by comparing their findings with databases that detail insect populations at various stages of development and assorted conditions.
The more species that are present the better. This is because overlapping data will provide researchers with statistical confidence and precision in the estimated time of death.
In some suspicious death cases, insect evidence may prove that the body was moved at some time after death. Some insects live in quite specific niches, such as on limited vegetation types, at certain elevations, or in particular climates. If the body yields an insect not known to live in the area, this can be prime evidence that the body was moved.
In cases where they suspect a person may have died but the body is missing, forensic experts know that a dead body lying on the ground will release all of its fluids into the soil below. This causes native soil organisms to leave the area as the pH rises and a whole new community of insects will inhabit this gruesome niche. This evidence can then be used to prove the exact location of death.
These are only a few of the many ways that insects are used to solve crimes. Crime scene investigations . . . are you ready for a new career?
