Maths key to DNA identities

Dr John Buckleton applies complex formulas and developing software to speed up DNA identification of corpses. Picture / Dean Purcell

John Buckleton mutters something about 10,000 bodies but gives an upbeat "yep" when asked if they can all be identified. He is talking about Thailand, of course. And he's being optimistic.

As international forensics teams, including those from New Zealand, take samples from thousands of badly decaying bodies in Thailand - the people who died when giant waves struck Asia on Boxing Day - this driven former shepherd turned highly skilled forensic investigator is doing the maths from his office at the Institute of Environmental Science and Research in Auckland.

Dr Buckleton's maths is not about counting bodies He is applying complex formulas and developing software to speed up DNA identification of these bodies.

Scientists and mathematicians will lead the next big assault on this mass disaster victim identification project, struggling to cope with the sheer scale of the worst natural catastrophe in living memory. Identification of thousands of bodies by other means, such as driver's licences in pockets, could be complete within weeks.

But the rest, possibly 10,000 tourist and Thai tsunami victims, will be identified by DNA, which could take years.

Buckleton is almost disappointed not to be in Thailand and is still hoping to go. He is not being ghoulish: DNA is his field and his passion.

The 46-year-old has worked on homicides and rapes in New Zealand, on celebrity cases such as OJ Simpson and the Russian Royal family, and was instrumental in setting up Britain's, and then New Zealand's, sophisticated national DNA databases. New Zealand's database claims a 52 per cent hit rate - the highest in the world - at placing criminals at their crimes.

The ESR already has a history with Thailand. Last year, the ESR installed a system for Thailand's criminal DNA database. Buckleton is now adding to it so it can analyse DNA from tsunami victims and their relatives so the sums do not have to be done by hand.

Although he would like to be at the disaster scene to help to train local mathematicians, he says at this stage his work can just as easily be done from this ESR building, with its rooms labelled "Danger, Keep Out," and photographs of firearm patterns on the walls.

He also has to leave soon to do training for the Australian federal police, teaching body identification from skeletised remains in the Solomon Islands.

He is qualified to get his hands dirty but says his specialty in the tsunami project is the maths.

"It's very dry but it's the bit where people have collapsed in the past. This is big. This is four times bigger than September 11. The problem isn't four times bigger, it goes up exponentially."

He knows his stuff. He and two colleagues have just released a how-to book on forensics and DNA - Forensic DNA Evidence Interpretation - an international manual for students and experts alike. It is already in universities.

It is not for everyone - the chapter on disaster victim identification includes some daunting mathematical formulas such as: Pr(GB, G1...GN\Hp,I)Pr(GB, G1...GN\Hd,I)LR= But the science is broken by chapters that Buckleton describes as "light relief" from all the maths - Waco, the OJ Simpson Case and the Russian Romanov family.

The chapter on disaster victim identification is, of course, timely for the Thailand disaster where, unlike Sri Lanka and Indonesia, many of those killed were tourists. Their bodies have been preserved as best they can be in such a hot climate so relatives can claim them and one day put them to rest.

The Thai people, too, are desperate for the bodies of thousands of their loved ones, so they can be set free for their next life with the appropriate Buddhist ritual.

Buckleton is well aware of the awesome scale of the task. An airline crash of 300 people can bring a laboratory to its knees, he says. But when terrorists ploughed aeroplanes into the World Trade Centre in New York in 2001, the problem of identifying so many mangled bodies escalated to a new high.

He thinks around 1000 families still have not had any body parts returned. Four years later the work continues.

Asked if it could take even longer to identify all the people in Thailand, he says the aim has to be faster, to give dignity to the deceased and closure to the families.

DNA identification of victims in Thailand is being carried out by what is called pedigree analysis - matching the dead person's DNA with the DNA of living relatives.

"Let's imagine a huge list of 10,000 pedigrees and 10,000 bodies, you've got to get the bodies back into their proper pedigrees and it's a substantial problem."

Buckleton has already tabulated the "easy" pedigrees, such as DNA from two parents missing a child, but more complex ones involving siblings and other relatives are still to be done.

The longer it takes to get samples from bodies, the bigger the challenge. The problem in Thailand is decay. "We get a thing called locus drop-out. It's latin for place, so these are bits on the DNA. When your body degrades your DNA degrades and your locii drop out."

The more the decay the less information and the more the ambiguity in the pedigrees. "So you could end up with a body that, you know, pitched loosely to two or three pedigrees. So you have to say, well, there's a body that could belong to this family, or this family, or this family."

All will be okay in Thailand as long as the bodies are sampled before there is too much degradation. "This is what makes me a bit nervous. As long as the technical work at the other end's happening we can do the rest."

When asked if he is confident it is happening, he pauses and says, "I am concerned."

As the bodies degrade, forensic scientists must turn "inwards".

With a fresh corpse a buccal scrape, taking cells from the tongue, is possible, matching the scrapes provided by relatives or those demanded by police in criminal cases. A single cell is enough for forensics scientists to work with. Sometimes blood can be taken from a corpse, but after a few days it is not possible and the scientists must turn to muscle and eventually bones.

It sounds so grisly, yet Buckleton seems such a cheery man, and forensics, which so fascinates the public it has spawned a glut of television shows, seems glamorous. Not really, says Buckleton.

"Come with me," he says, going into the hallway and pointing at a series of photographs on a wall. A man lies prone and bloodied on the ground. Crime is not glamorous, he says. This was a real person and it was Buckleton's first homicide case.

"It was a cold September morn in 1986 when Mr [Bill] Worrall was found dead in the driveway of his own sharemilking business in Takanini," he begins, falling easily into the talk he also gives trainees.

"He has three shots to him. Can you see these little pellets here? Your job as a forensic scientist is to work out what happened and who did it. Now, there's a blood trail leaving Mr Worrall, it's human blood but it's not his."

Worrall had gone outside with his double barrelled shotgun, was fired on and let off shots of his own hitting the offender.

Cutting the story short, Buckleton lies down on the corridor floor to demonstrate Mr Worrall's position: "Mr Worrall calls out to his wife, 'Help me, Kerry'. I don't know what Kerry said, but what she could have said is, 'I'm not going to help you, I'm paying $15,000 for this'."

Worrall's wife and the hit man, Brian Tomlin, were jailed, and Buckleton's career in forensics was on its way.