The world’s largest experiment to simulate dead bodies in suitcases is underway: ScienceAlert

A crime scene can appear in any shape and size.

In recent weeks, a family in Aotearoa New Zealand who bought abandoned goods from a storage locker made the gruesome discovery of two sets of human remains hidden inside two suitcases.

Unfortunately, this is not a unique case – the bodies of murder victims are found in suitcases with amazing regularity.

But they present a particular challenge to the police investigating crime, which is where forensic science comes in.

Why bags?

Forensic case history and crime news are sadly filled with corpses found in suitcases, briefcases, wheelie boxes, car trunks, refrigerators and freezers.

Examples of such finds include a suitcase in a crowded train station in Tokyo in 2015, a suitcase on a Seattle beach in 2020, and the 2019 case of human remains in a suitcase left on the side of a highway in South Australia.

There is a simple reason why bags are so common in these situations. While most crime movies depict bodies left above the ground or buried in secret shallow graves, in reality murder victims are often hidden in last-minute tidy objects.

These are easy to get hold of, accessible, large enough to fit the body, and easy to transport (preferably on wheels). They may also hide the smell of decomposition for some time – it is beneficial for the criminal to find an argument or disappear.

Forensic researchers call such places “limited access environments,” because they limit, delay, or completely impede one of the natural steps that occurs after death: the arrival of hordes of insects.

The job of scientists such as forensic entomologists is to help investigate crimes, but also to develop research that makes this task less difficult.

Insects are the key

In a forensic investigation involving a decomposing corpse, forensic entomologists can use insects to help estimate time since death, track the movements of criminals and victims, and determine the presence of drugs and alien DNA.

Carrion insects—such as blue and green bottle flies, meat flies, house flies, and coffin flies—have highly specialized olfactory systems that they use to detect decomposing scents.

If a carcass is left undisturbed on the ground in a temperate environment, carrion insects will soon colonize it, attracted to the odors produced by the bacteria-mediated decomposition process.

Within a few hours, the insects will lay eggs on the orifices and wounds of the body, and the small larvae that hatched from them will begin to devour the body.

But the travel bag limits the arrival of insects. So far, forensic research on how insect participation changes in these limited access environments has received little attention.

To date, only two pilot studies on the pouch decomposition process have been completed, one in the UK and one by our team in Western Australia. Both studies show that carrion insects are very resourceful when it comes to reaching hidden objects.

jungle bags

Hidden in a patch of bush in Western Australia, we are currently conducting the largest ever experiment with the decomposition process in suitcases and wheelie boxes, with nearly 70 specimens.

Luggage and wheelie boxes are used with dead pigs in the largest limited access environment study to date. (Paola Magni)

This first-of-its-kind work will provide useful data for investigating similar cases around the world. Each wheelie bag and basket contains a dead piglet, simulating a cadaver; Controls are placed in the environment for comparison.

We have put in place tools to record temperatures, humidity and rainfall both in the field and in containers.

The experiment began in early winter 2022 and will end in the summer. The first data will be presented at the world’s largest forensic science conference in February 2023.

Despite an initial delay in getting to the insects during the cold, rainy Western Australian winter, within a month of the bags we noticed clusters of eggs of blown flies on and around the bag’s zippers.

When we opened the bags at set intervals, we found fly larvae, along with coffin flies and some active beetles in the remains. This means that the offspring of large flies and beetles must reach the body through the teeth of the zipper.

Meanwhile, smaller flies can cross the zipper as adults, and lay their eggs directly on the decomposing remains.

Once the larvae complete their life cycle and emerge as adult flies, none of them can escape from the pouch. These trapped insects represent a rich source of information, as we know the habits and growth rates of different species, and can find toxicology data preserved in their exoskeletons.

From this perspective, a forensic entomologist can infer the time or season of death, the possibility of the body being transferred, and help explain the causes and circumstances of death.

Investigating human remains in a Pandora’s box suitcase is often fraught with complex problems. But with the help of a humble carrion-eating fly trapped inside, we gain a treasure trove of vital information that can help us solve crimes.Conversation

Paula Magni،, Senior Lecturer in Forensic Science, Murdoch University

This article has been republished from The Conversation under a Creative Commons license. Read the original article.

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