How insects hold key to solving crimes and mysteries from beyond the grave

THERE can’t be that many people in the world who are so very intimate with the life of the phoridae, a family of small, hump-backed flies resembling fruit flies.

Phorid flies can, apparently, often be identified by their escape habit of scuttling across a surface rather than taking wing. The most well-known of around 4,000 species is Megaselia scalaris, commonly called a “coffin fly”, so named because they breed in human corpses with such tenacity.

For this reason, they are important in forensic entomology – or the study of insects as it’s otherwise known.

Dr Stefano Vanin’s desk in his lab at the University of Huddersfield doesn’t exhibit signs of his personal life or his love of walking in the Pennines (or even the Appenines, not far from where he grew up in northern Italy). This environment needs to be kept as clean as possible, and the only objects of interest are a microscope and bags and jars which apparently contain soil or dust.

“Go on, have a good look,” says Dr Vanin, taking a small instrument and gently sifting the soil to reveal the wings, limbs and abdomens of dead flies. A tall lidded glass jar looks like a scientific version of a yard of ale, except that it has been filled to about a third of its capacity with soil.

This piece of kit, he says, is very useful for measuring how far insects will burrow in search of food. The tasty morsel buried near the bottom of the jar is a little lump of pork, the meat most closely resembling human flesh.

“They can dig down two metres. They smell the food and they need to feed to procreate. It’s like a human being locked in a room and hungry, knowing there is a delicious cake in the room next door. You’d break down the door, wouldn’t you...”

Dr Vanin came to Huddersfield two years ago as senior lecturer in forensic entomology, having made a name for himself through his previous research work at the University of Padua in Italy, as well as in France and the US.

Apart from teaching the next generation of forensic scientists (including a large group sent over from Libya because of the university’s expertise in the field), his world-renowned and wide-ranging investigations have included work on mummified bodies including that of a First World War soldier and on an ancient Egyptian mummy.

He’s been called on to lend his expertise to modern day questions around the decomposition of the human body in murder cases, where study of insect incursion enables him to estimate time of death. If a body is found within 72 hours of death, evidence such as body temperature and rigor mortis can be used to establish when the death happened. However, if the death happened more than 72 hours before being found, the evidence of insect activity becomes a vital factor in establishing a timeline.

Dr Vanin also helps unlock secrets that have been buried in the much more distant past and, last year, he was asked to join a team investigating one of the most exciting and extraordinary archaeological finds of the past century.

A huge number of perfectly mummified bodies had been found in a sealed and forgotten crypt of an obscure Italian church during restoration work. Much of their clothing was intact and corpses were still clutching religious artefacts or the tools of their worldly trade, preserved beneath the 15th-century Church of the Conversion of St Paul in Roccapelago di Pievepelago.

The 281 citizens had been laid to rest in a common tomb between the 16th and 18th centuries. They were found to be people of all ages and stations in life, and the unusual microclimate of the area meant around 60 bodies were perfectly preserved by natural mummification.

A range of scientists from physicists and biologists to anthropologists and archaeologists are collaborating to build a scientific, social and historical picture from what is regarded as a momentous find. Dr Vanin compiled data from mites and insect cocoons that remained on and around the mummified bodies, some of which were brought to Huddersfield for analysis.

One of the important contributions he makes is a scientifically-based opinion on the season of death as well as the kind of diseases people died from.

Patterns of insect infestation can also give vital clues as to the general health of a population. These are affected by climate and where a body is left when dead – so in a warm field flies will do their work much faster than in a more closed environment. Contents of the insects’ digestive tract are of particular interest.

Dr Vanin has worked on the remains of a French Revolutionary Army soldier who was involved in the Battle of Le Mans in 1793, looking for evidence of the population’s health at the time by extracting DNA from parasites.

“From the pathogens we can find which insects were the vectors (vehicles) of disease. If I find a tick or flea I look inside it for the pathogens responsible for disease. Then I look in the human remains and check if the same pathogen is present in them. Then I can say if this insect is responsible for transferring the pathogen from one person to another.”

In a collaboration between the universities of Huddersfield and Pisa, he is studying “fardos” – Peruvian mummies found in a foetal position with evidence of food offerings and funerary artefacts beside them inside rolls of fabric. The coastal-living tribe known as the Moche, lived up to 1,000 years ago. Their remains were found and were taken to Italy in the 18th-century by a rich explorer and collector who later donated them to a museum.

Dr Vanin and two PhD students have travelled back and forth to examine the bodies, some of which (including children) had been decapitated. Peeling back the layers of cloth and time, then plotting the interaction between insect life and human decomposition will reveal many valuable insights into life in Peru pre-European colonisation, says Dr Vanin, who quickly established that the fardos had been moved from place to place since death.

“Some of the most urgent questions to answer are around how healthy people were back then. We will learn so much, including the epidemiology of certain illnesses, building up a picture of what happened to the local population when the Europeans arrived with new diseases, whether they took new pathogens back home with them, and whether pathogens found in the Moche people had any contact with people from Africa, as some people believe.”

Among the scientific techniques Dr Vanin has pioneered is his recently published new protocol for the extraction of human DNA from insect larva that have fed on human remains. The material is found inside cocoons shed by the larvae as they mature.

This provides a method for establishing, where a body has not been found in a murder case, that a body has actually been in a certain location but then moved.

“It was a dream of mine that we would make this breakthrough,” he says. “It will demonstrate that a body was there, and will be valuable in cold cases and old cases.”

His work has an element of the popular CSI detective series about it, but he says he’s in the lab until late in the evening most days – and wouldn’t watch such programmes anyway.

“They generally misrepresent science, to be honest. Everything seems to be solved in 30 seconds, cases are cleared up in a week and no-one ever makes a mistake. Science, and real life, just aren’t like that.”

What is it about insects that so engrosses him? “They dominate the world. Humans do not dominate the world – ants are more important than humans...You can find insects adapted to all environments, from very cold to very hot, and even find them beneath glaciers.

“They show a flexibility in their biology that is amazing, so they have power and beauty that add up to a 360-degree fascination 
for me.”

Killer brought to justice

Dr Vanin played a key role in one of Europe’s most notorious murder investigations, which resulted in Sicilian Danilo Restivo being found guilty of the killing of Heather Barnett in Bournemouth in 2002.

Restivo’s first alleged murder victim was Italian girl Elisa Claps in 1993.

Her body was not discovered until 2010, but a link – the fact that Restivo cut the hair of his victims – was made between the two crimes.

Dr Vanin was asked to estimate the season of Claps’s death. He analysed changes to the crime scene caused by insect activity and found she had been killed in the autumn, some time soon after her disappearance.

Restivo is serving a 40-year sentence for killing Heather Barnett.