By Daniel Schweimler
BBC News, Buenos Aires
The remains of hundreds of people killed during Argentina's military dictatorship about 30 years ago have been found in a pit.
The thousands of bone fragments were found at a former detention centre.
Investigators say the discovery proves that the authorities tortured, killed and burned the bodies of their political opponents.
Human rights groups and survivors have made such allegations but the military deny them.
The official figures say that 13,000 people were killed under military rule in Argentina in the late 1970s and and early 1980s.
But the families, survivors and human rights campaigners say many more - up to 30,000 - were kidnapped by the authorities and taken in unmarked cars to clandestine detention centres.
There they were tortured and killed.
But many of the bodies have never been found and the authorities eliminated all record of their grisly actions.
These victims became known as "the disappeared".
But the families and forensic investigators have never given up their search for truth and justice.
And this find - 10,000 human bone fragments at a former detention centre in the city of La Plata, just south of Buenos Aires - they say confirms what they have always said.
They are still working on the bones, but say the evidence uncovered so far shows that the bodies were thrown into the pit, covered in fuel then set alight alongside tyres to cover the smell of burning flesh.
Two hundred bullet marks were found in a wall bordering the mass grave.
Civilian governments in the 1980s and 1990s pardoned many of the perpetrators of what became known as the Dirty War.
But the trials resumed a couple of years ago and a small number of minor officials have been prosecuted and sent to jail.
Critics say this latest find will remind Argentina that justice has still not been done for one of the darkest periods in the country's history.