Helping to identify Brazil's disappeared

In 1990, a mass grave containing 1,200 bodies was discovered on the outskirts of the Brazilian city of Sao Paulo.

It is thought that most of these were poor people and vagrants, but political dissidents were also buried there.

Now British scientists are helping to identify the bodies, which are believed to date from the days of military rule, which ended in 1985.

Brazil timeline
1964: Left-wing President Joao Goulart ousted in military coup. Repression begins.
1985: Military rule comes to an end. Civilian Tancredo Neves elected President.
1990: Mass grave discovered at Dom Bosco, on outskirts of Sao Paulo
British scientists help identify two of the 1,200 bodies at Dom Bosco.

The late 1960s and 1970s were dark days in South America for democrats and left-wingers.

In Chile the excesses of General Augusto Pinochet's regime are well chronicled, as is the "dirty war" conducted against political opponents by the Argentine military junta.

But less well known are the human rights abuses perpetuated by the Brazilian military rulers.

President Joao Goulart, a supporter of land reform and income redistribution, was ousted in a bloodless coup by the army in 1964.

For the next 21 years, Brazilian generals retained the upper hand and, as the economy boomed, the United States and other Western powers kept silent about persistent reports of human rights abuses.

Eventually, civilian rule was restored and in 1990 the discovery of a mass grave on the outskirts of Sao Paulo gave the first indication of the scale of human rights abuses under the military.

In 1995 the Brazilian Ministry of Justice set up a special commission to address the isssue of Brazil's Desaparecidos Politicos (Missing Political People).

The Comissao Especial Mortos e Desaparecidos (Special Commission on Dead and Missing Political People), headed by Luiz Francisco da Silva Carvalho, is made up of MPs, soldiers and relatives of the victims.

For 12 years the skeletonised bodies found near Sao Paulo have remained unidentified.

But now British forensic scientists, working hand in hand with colleagues from Brazil, have begun putting names to the corpses.

Dr Martin Evison, from Sheffield University, said he had used a new DNA extraction technique to positively identify two of the bodies.

He has been working with Dr Marco Guimaraes from the University of Sao Paulo's Faculty of Medicine at Ribeirao Preto.

Dr Guimaraes has now returned to Brazil and will share what he has learned with forensic pathologist Dr Daniel Munoz, who has been appointed by Sao Paulo state government to oversee identification of the 1,200.

Dr Evison, a forensic pathologist, has experience of analysing ancient skeletons but more recently his department also worked with South Yorkshire Police, who were investigating the discovery of a skeletonised body in a holdall.

It was eventually identified as that of 75-year-old Mohammed Nasser Ali and his son and grandson were later jailed for life for his murder.

Dr Evison explained the process involved in the identification of the Brazilian bodies.

He said for some bodies - those which had clothes, jewellery or other identifying marks - DNA samples from living relatives could be compared with DNA extracted from the bones.

For others they would obtain forensic anthropological clues - such as gender, probable age and medical history - and may use facial reconstruction techniques.

The reconstructed faces could then be shown on Brazilian TV or in newspapers in the hope that relatives or friends would recognise them.

Dr Evison, who plans to travel to Brazil to carry out further work, said he was delighted they had been able to extract DNA samples from the bones.

"These bodies have been in the ground for 30 years and the climate is warm and moist, which is ideal for DNA degradaton.

"Nearly all the DNA had gone, so we needed to use a DNA purification process to obtain the best results."

Dr Evison said: "This involved decalcifying the bone, using an enzyme to digest protein in the sample and then binding the DNA to silica, which is basically a pure ground glass.

"This means we can then wash away any impurities. We then wash it off into water to create a DNA solution."

Dr Evison said: "How they died is a judicial issue but if we notice, for example blunt force trauma to the head, we will pass that information on to the authorities."