How insects help forensic experts in a criminal investigation?

Forensic science has become an important field where the application of different areas of science is used to solve a criminal case and capture the persons involved. Therefore, forensic Entomology has become one of the crucial sectors for Forensic experts.

Entomology deals with the study of insects at a Taxonomic, morphological, paleontological, biochemical, and genetic level. Its application in Forensic science has helped in many criminal cases to determine and support the facts presented in the court.

Forensic entomology is the scientific study of insects in legal matters. The insects are collected, identified, and studied found around the dead body to solve criminal cases. The insects involved in the investigation include Arthropods, Centipedes, Arachnids, Millipedes, etc., for criminal cases.

Here, in this article, we will discuss how these insects help in criminal investigations since the insects are used majorly for information.

Use of Insects in a criminal investigation

Estimation of Time since death

Time since death or Post-mortem interval determination is the systematic investigation used by Forensic pathologist or medical examiner with the assistance of a Forensic entomologist for information regarding “Time since Colonization,” which ultimately helps in determining Time since death.

Post-mortem interval is determined by the age cycle of the insects and the faunal succession schedule of different species.

Linking Suspect with the crime

Using insects for linking the criminal to a crime is an extraordinary way. We have witnessed dogs be used in criminal investigations for capturing drugs, alcohol, suspect, bombs, etc. but not in many cases flies have been used. However, there is one recorded case of the 13th century where the flies were used for linking the Suspect.

Case study: In the 13th century, a Chinese magistrate investigated a murder in the rural area of a farm where the laborers were involved in harvesting paddy crops. The victim has sickle wounds, and many laborers on the farm used sickles. The investigator collected the sickles from all the laborers and kept them in the open, warm sunlight. Soon, flies were attracted to one of the sickle and not to the rest. It was presumed that the particular sickle had blood on it.

Detection of Drugs

In the cases where the Flesh of the body is not enough for drug testing, the insects crawling on the body are collected. The drug, if present, will have been accumulated by the larvae. The drugs present in the body also affect the age cycle and development of the insects.

The fate of drugs in the entire body of insects depends on the development of species, the drug’s action on their body, absorption, redistribution, metabolism of drugs in the insects.

Presence of Wounds

In a decomposing body, the insects colonize inside the dead body through the natural orifices unless there is a wound present in the body. In the case of an injury, the insects will crawl through the injury inside the body. Therefore, these insects help determine wounds if they are formed by a gun or a sharp object, or blunt force.

If the body was moved/Transferred

In some cases, the criminal transfers the victim’s body to a secondary crime scene for hiding or burying. In these cases, the insects found inside the body may be present from the primary crime scene indicating the transfer. They may also help in determining the habitat of the primary crime scene where the victim was killed.

Illegal Poaching

Forensic Entomology has also helped in the Wildlife forensics for Illegal Poaching. In Canada, a few years ago, two black bears were shot dead by two men who were found hiding near the bear by the witnesses who came after hearing the gunshots. They also spotted a vehicle and confirmed to the police that the car belonged to the suspects. However, to build a strong case, the policemen took a blowfly from the bear’s bodies to an entomologist named Anderson. By determining Time since death, keeping in mind all the factors and the statements of witnesses, the presence of the two witnesses near the crime scene was confirmed.

Child Abuse

Insects are also helpful in determining Child abuse. Insects such as Green bottle fly are attracted to the odor of ammonia released from Urine or fecal contamination. These flies hatch eggs near that area. If left undiscovered or taken care of, they will hatch into maggots feeding on the Flesh, ulcers, or wounds on the body caused by abuse. The Flesh in that area will be eaten and further infected by the bacteria. This process is known as Myiasis.

Authored By:

Forensic Yard