Page last updated at 15:50 GMT, Saturday, 15 November 2008

Buried pigs provide murder clues

A pig being lowered into the ground by scientists
The study could help police find murder victims' unmarked graves faster

Scientists in Staffordshire have been using dead pigs and geophysics to develop research that could help police find the buried remains of murder victims in unmarked graves faster.

Five pigs that were destined to be sausage meat have been buried in shallow graves on the Keele University campus, in Stoke-on-Trent so scientists can study their decomposition.

Researchers said it meant they could build up a template which would help police recognise buried human remains in typically British areas like woods and moorland, when sweeping areas with specialist geo-physical instruments.

In the US, the law in some states allows similar testing to be carried out on human corpses, but that data is based on decomposition rates specific to the US climate and soil.

Head researcher Dr Jamie Pringle said pig flesh had similar properties to human flesh, which was vital for a decent comparison.

He said: "We're not allowed to use human tissue in the UK, so pigs are a good second choice.

"Similar size to us and have similar hair, skin and body-fat ratio."

We're not allowed to use human tissue in the UK, so pigs are a good second choice
Dr Jamie Pringle

The 12-stone pigs were reared on an organic farm in Stoke-on-Trent and had previously been destined to be sausages, Dr Pringle said.

Some of the pigs were wrapped in plastic, while others were left "naked" in the graves, as 75% of human remains found by police were partially clothed or covered.

The four-month-old pigs were buried in December 2007 and their graves are tested each week with geo-physical instruments, including ground-penetrating radars used by utility companies for detecting underground cables and pipes.

Radar readings allow the scientists to build up two-dimensional vertical slices to make a three-dimensional image.

The resulting images will show a contrast between the body and the background material, alerting searchers to a potential body.

Fluids from pigs have contrasting properties that can sustain electric fields, which are reflected in the radar's beam.

The beam shows up as a bright blue patch on data, alerting searchers to a potential body.

PhD student John Jervis said: "This equipment transmits a pulse of radar energy into the ground.

"If there is anything with contrasting dielectric properties that will reflect that energy."

The team also used electrical currents to measure the level of resistance in the ground for any anomalies in the soil.

Tests have found that the fluid from a decomposing pig becomes increasingly conductive over time, 1,000 times more conductive than the surrounding soil moisture after a year in the ground, while tests on the wrapped pigs showed the current was forced to travel around the pig's body.

Serial killers

Similar geo-physical testing was used to find the bodies in the Fred West case.

Fred West, who was charged with 12 murders, escaped trial by committing suicide in his prison cell in January 1995.

His wife Rosemary West, now 50, was sentenced to 10 life sentences in November 1995 for the murder of 10 young women and girls.

Most of their victims were buried underneath the Wests' house at 25 Cromwell Street, Gloucester.

The team has also been working closely with experts from Staffordshire University.

Professor John Cassella, of Staffordshire University Forensic Science Department said: "What this research shows is that there is an optimum time for detecting bodies using geo-physical techniques.

There is a window of five to eight weeks after the body is buried when the signals are strongest
Professor John Cassella

"There is a window of five to eight weeks after the body is buried when the signals are strongest.

"After that the signal becomes weaker and weaker.

"If the police know a body has recently been buried, they might be better holding off for a couple of weeks before they use this technique to find it.

"This knowledge could help them narrow down the search area they need to examine."

Keele researchers said they were using their techniques in an ongoing murder investigation with police, but would not be drawn on the inquiry.

Dr Pringle said he hoped the data would provide a "gold standard" for helping police in their search for murder victims.


Pigs have similar flesh to humans

Print Sponsor

Universities try new grading plan
20 Oct 08 |  Education

The BBC is not responsible for the content of external internet sites

Has China's housing bubble burst?
How the world's oldest clove tree defied an empire
Why Royal Ballet principal Sergei Polunin quit


Americas Africa Europe Middle East South Asia Asia Pacific