A bone wrapped with rope and skull fragments scattered over a cactus-covered desert field are grim testament to a 1996 massacre of more than 1,200 prisoners by Muammar Qaddafi's regime.

Libyan officials announced Sunday that they found a mass grave believed to hold the remains of the victims outside the white walls of Tripoli's Abu Salim prison, where Qaddafi locked up and tortured opponents or simply made them disappear. Excavation has not begun, but several bone fragments and pieces of clothing already have been found in the topsoil.

Those bones could offer some of the most damning evidence of the brutality of Qaddafi's nearly 42-year rule, and allow relatives of the victims to learn the truth about their fates after years of regime stonewalling. They also hold symbolic importance to the Libyan revolution itself, which was sparked in mid-February in the eastern city of Benghazi by demonstrators demanding the release of a prominent lawyer representing the families of slain inmates.

"We have discovered the truth about what the Libyan people have been waiting for for many years, and it is the bodies and remains of the Abu Salim massacre," military spokesman Khalid al-Sherif said at a news conference.

Soldiers and relatives sifted through the sand during a visit Sunday, displaying a pair of pants and other remains for reporters brought to the site. One bone had a rope tied around it, possibly from a prisoner who had been bound. A group of former rebels at the site shouted "Allahu Akbar" -- "God is great" -- as relatives wandered through the area.

Al-Sherif and members of a committee tasked with finding mass graves said they were confident the field holds the remains of the prison massacre victims based on information from witnesses, including former security guards who have been captured in the fight against the authoritarian leader.

Qaddafi has been in hiding since revolutionary forces swept into Tripoli in late August, though his supporters continue to fight in several parts of the country. He, one of his sons and his intelligence chief face international charges of crimes against humanity for the regime's bloody effort to wipe out anti-government protests this year, but not for earlier killings.

The June 1996 massacre occurred after inmates rioted to protest their treatment. Guards responded by opening fire on them. Al-Sherif said authorities believe the bodies were kept in the prison before they were buried in 2000.

The killings became a focal point for Qaddafi's opponents. Most of the inmates were political prisoners, including Islamic clerics and students who had dared to speak against the erratic leader, who wielded almost complete control over the oil-rich North African nation.

For many years, families of those killed were not told the truth and were barred from visiting, but reports about the shootings began to emerge after one of the guards spoke out and human rights groups began to investigate. Qaddafi had agreed to pay the families compensation, but activists insisted that those responsible be brought to justice.

Ibrahim Abu Shima, a member of the committee looking for mass graves, said investigators believe 1,270 people were buried in the field, based on a list of prisoners reported killed. He stressed that Libya needed help from the international community to find and identify the remains because they lacked sophisticated equipment needed for DNA testing.

"We have no expertise with this," he said. "We need help to dig, to remove corpses and remains without mixing them."

The Geneva-based International Committee of the Red Cross has said at least 13 mass graves have been found in Libya since Tripoli fell.

Soaade Messoudi, a Red Cross spokeswoman in Tripoli, said the organization dispatched two forensics experts this month to help with the management of human remains. But she said the organization is not involved in collecting evidence that could be used in any legal proceedings.

"We urge the people to be careful in uncovering human remains," she said. "This could really affect any possible recovery of the identity of these missing persons."

The New York-based group Human Rights Watch has urged Libya's transitional government to keep mass grave sites secure and to stop exhuming remains until it can be done properly.

Sami al-Saadi, who said he lost two brothers in the massacre and was himself imprisoned at one point, said it was important to bring closure for relatives who have gone years without knowing where their loved ones are buried.

He said he had rejoiced when revolutionary forces succeeded in ousting Qaddafi, but the memory of his brothers Mohammed and Adel cast a shadow over the celebrations.

"The people who are responsible for this massacre should be brought before a judge and we can give now sure evidence to all the world about Muammar Qaddafi and how this dictator led this country and its people," al-Saadi said as he stood in the field, walls lined with barbed wire towering behind him.

Mabrouka al-Sayed said she has waited years for news of her son Abdul-Aziz, who was believed killed in the massacre. She said representatives from the prison claimed he died after becoming ill but she didn't believe them. They never returned his body, giving her only a death certificate.

"I've been in deep sadness because I didn't know where my son was," she said as she sat in a pickup truck with her grandson while male relatives went to see the field. "I feel great relief now that I know where his burial place is."

The prison itself, near what had been Qaddafi's sprawling compound, sits empty now. Its inmates were freed amid fierce fighting as rebels swept Qaddafi's regime from the capital.