| ATOYAC DE ALVAREZ, Mexico
ATOYAC DE ALVAREZ, Mexico Forensics experts began digging for secret graves on an army base in southwestern Mexico this week to find proof of government atrocities during the country's 1970s 'dirty war.'
Using high-tech scanners, picks and shovels, they searched for bodies of community leaders who were abducted by soldiers, taken to the isolated base at the Pacific town of Atoyac de Alvarez in Guerrero state and never heard from again.
Human rights advocates said it was the first time dirty war excavations have taken place at a Mexican military base.
The team is headed by Argentine experts with experience digging up evidence from that nation's dirty war.
Atoyac de Alvarez was the base of an armed guerrilla movement in the 1970s, and some 470 people "disappeared" from the town when security forces and senior government officials crushed leftists and students.
Survivors hope that finding the remains of their loved ones will lead to some sort of justice.
"They say the bones talk. The bones will tell us what happened to them; they will tell us if they were tortured," said Tita Radilla, whose father Rosendo was a community leader in Atoyac before he was arrested.
"I know my father was at the military base. Witnesses who were there saw him, but they never saw him leave," she said.
Rosendo, who built schools and medical clinics in Atoyac de Alvarez and briefly served as mayor, was arrested by soldiers for composing pro-guerilla songs, said Alejandro Juarez, a spokesman for a rights group who works with Radilla's lawyers.
The excavations could take several weeks as forensic specialists work alongside public prosecutors to scour the base's shooting range, basketball court, wells and latrines for signs of buried remains.
"We have no idea how many bodies could be buried on this military base," Juarez said. "But what we do have are eyewitness accounts from people who were detained on the base and saw farmers, social activists and guerrilla sympathizers getting tortured, killed and buried there."
CLAMPDOWN ON LEFTISTS
The Institutional Revolutionary Party, or PRI, which ruled Mexico for seven decades until 2000, clamped down hard on leftists in the 1960s and 1970s, but few officials were ever prosecuted for their actions.
Some 1,200 people disappeared nationwide, hundreds of them in Guerrero. Prosecutors say the campaign against them was mainly orchestrated by Luis Echeverria, the interior minister from 1964 to 1970 and president from 1970 to 1976.
Radilla's father disappeared in 1974 and she fought for decades to bring his case in front of an international court, putting pressure on the Mexican government to investigate.
The Argentine forensic investigators have an international reputation and are often sent to probe massacre sites around the world, having conducted extensive searches at home.
Echeverria, who painted himself as a leftist, is widely blamed for a 1968 massacre in Mexico City when police opened fire on student protesters, killing hundreds, shortly before the city was due to host the Olympic Games.
Now 86, Echeverria has been living quietly under house arrest in Mexico City since 2005 when prosecutors brought genocide charges against him. He has always denied any charges against him and attempts to bring him to trial have foundered.
"The Mexican government has always been very careful to guard its image as a protector of human rights. That's why not much is known about this time period," said Radilla.
"For us it was a catastrophe," she added.
(Additional reporting and writing by Mica Rosenberg; Editing by Eric Walsh)