Identifying skeletons in Georgia

Investigators are continuing the search for more bodies

Police say more than 300 bodies have now been recovered in their search of the Tri-State Crematory in Noble, Georgia, US.

The human remains were found stacked in storage sheds and scattered in local woods.

In a situation like Georgia there are enough of the remains identifiable to build up a profile

Dr Lee Meadows Jantz

The operator of the crematorium, Ray Brent Marsh, 28, has been arrested and charged with fraud - in the absence of any state laws prohibiting the desecration of corpses.

Whilst a gag order, imposed by judicial officials, currently prohibits authorities involved in the investigation from divulging further details of the search, it has been revealed that only 36 of the corpses have been positively identified.

Grieving relatives and friends who had taken their loved ones for cremation have been filling in forms to help the police with identification. But, in the end, it will be the scientific teams that will have to piece the details together.

Skeletal remains

Some of the deceased in Noble, which is about 135 kilometres (85 miles) north-west of Atlanta, are estimated to have been left for up to 20 years.

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The bodies range from the newly dead to severely decomposed, even mummified, said Kris Sperry, the state's chief medical examiner.

Scientists will piece skeletons together in order to identify individuals. Whilst it is not always possible to put together a complete skeleton, bones can be graded by sex, age and race.

It may also be possible to identify distinct features. For example, in cases where it is known that some of the individuals were elderly, scientists may also be able to identify bodies through their prosthetic limbs or the operation scars on the bones.

DNA testing

This work differs greatly from the situation that faced scientists who dealt with the aftermath of 11 September in New York.

"In a situation like the World Trade Center, they were heavily relying on DNA because they didn't have full skeletons; they had bits and pieces of soft tissue," Dr Lee Meadows Jantz, from the Anthropological Research Facility at the University of Tennessee told the BBC World Service's Science In Action programme.

"In those situations DNA is the only thing that you can do reliably because you don't have the time and you don't typically have as much of an individual as you need to build a profile."

Extracting DNA from the remains is increasingly being used to help identify the dead after disasters such as plane crashes where there has been a large loss of life.

It is a costly and time-consuming technique that involves comparing corpses and fragments of tissue with material taken from a missing person's comb or razor, or from a swab sample taken from the mouth of a close relative.

Visual identification

Scientists use enzymes to dismantle the DNA from a cell; they then pass an electric current through the fragments that makes them line up in a unique pattern like a barcode.

Officials do not know why the bodies were not buried

In Dr Jantz's view this type of testing is unlikely to be used in Georgia.

"There are enough of the remains identifiable as individuals that you can determine sex, race, age and any type of pathology marker," he said.

Sometimes a combination of methods is needed to identify remains beyond reasonable doubt.

The first line of inquiry is visual evidence - hair and eye colour, height and weight, and more specific clues such as scars and tattoos.

Long investigation

Identification by relatives tends to be avoided both because it is too distressing when bodies are mutilated or decomposing, and because relatives sometimes misidentify remains.

In cases where human remains are scattered, dental records are often used. Teeth are the strongest material in the human body, and often survive when nothing else does.

Even a single tooth can be matched with X-rays taken by dentists and in a wealthy country such as the United States, many people will have had some hi-tech dental treatment where good records are kept.

A federal disaster mortuary or "de mort team" team has now moved to the crematorium in Georgia. They are trained to deal with the aftermath of disasters.

Investigators say they are likely to be at the site for another eight months.