An insight into the complex experiments involved in forensic science.
Crime is everywhere but, thanks to our advancing technologies, what is becoming rarer is the unsolvable crime. Poulomi Bhadra, Forensic Science MSc student, is a step closer to putting a complete end to this genre of crime.
The research of many students at King’s in the field of forensic science proves invaluable to the Metropolitan Police Service in criminal investigations.
Dr Barbara Daniel, Head of the Department of Forensic and Analytical Science at King’s College London, said, “King’s researchers work together with the MPS, sharing expertise and resources, to enable King’s students to carry out focused research projects based on real crime scene investigation. The aim of these projects is to tackle the challenges in uncovering, collecting and analysing forensic evidence. As a leading research institution we are now building on this experience and drawing from other expertise across College to work with the MPS on expanding our work in digital forensics and cybercrime.”
Poulomi’s research focuses on forensic entomology, using the developmental stage of flies or their larvae (or other insects) to determine when a victim died.
Blowflies are mainly used as they are the first insects to arrive on a corpse and hence make it easier to estimate the time of death. However, scientists have to take on board the factors that may delay the process of the flies’ arrival. Factors such as if the body is indoors or outdoors, buried or in a vehicle, all contribute to the time bluebottle or greenbottle blowflies find the body.
Poulomi is looking at how long flies take to arrive when a body is in a suitcase. She is investigating various types of zips on luggage – metal and plastic toothed zips and coiled zippers – to see how long colonisation takes on each. Although to the naked eye zips appear to be pretty tightly sealed, on a microscopic level they actually have tiny gaps, large enough for female blowflies to plant their eggs.
An experiment was set up simulating a real case scenario, where a pigs head bought from a butcher was placed in an airline cabin suitcase and put in a cage in the wildlife garden in the Natural History Museum. What was observed was it took at least 24 hours for eggs to appear on the case, this could make all the difference from a detective’s perspective. The tiny first born larvae were observed crawling on the zipper until they disappeared, only to reappear after a week as well fed, large larvae dispersing from the suitcase to find grounds to pupate – the next stage of blowfly development.
Her findings have proved that blowflies are capable of laying eggs on different kinds of zips when attracted to the smell of decomposition e.g. a rotting corpse! Eggs were deposited pretty much anywhere on the zips, from the crevices of the zip teeth to the actual zip tape and even on the underside of the zip.
Forensic entomologists have been curious for several decades at the role of insects in crime scene investigations. Working closely with pathologists, they have been able to provide a more accurate timeline of victims’ deaths to assist police investigations.
Poulomi’s work in this field contributes to the work on ‘oviposition’ – where flies choose to position their eggs – in criminal cases. Further research into this area of forensic entomology will help in a more precise determination of a victims’ deaths in enclosed cases with restricted access and as a whole could help solve a crime!