La Serna del Monte, Spain - In the night of August 14, 1936, Jose, Juan, Nicolas and Francisco Gutierrez were asleep in their parents' house in La Serna del Monte, a village north of Madrid.

Spain was through living turbulent times. A month earlier, a military uprising instigated by right-wing General Francisco Franco against the leftist republican government had unleashed a civil war.

The Gutierrez brothers, who were aged between 18 and 38, had come down from Madrid to help their father with harvest work at the village, which was occupied by Francoists.

That night, "some men got them out of bed, put them on a truck and just shot them dead on the outskirts of the village," Jesus Gutierrez, a nephew of the victims, told Deutsche Presse-Agentur dpa.

"They were no reds," the retired electrician stresses.

Francisco belonged to the Socialist trade union UGT, but the nephew finds that an insufficient explanation as to why Franco's supporters executed "simple labourers," probably throwing their bodies into a mass grave.

"Maybe they were killed just to frighten people," says Gutierrez, one among thousands of Spaniards who feel they can get no rest until they have retrieved the remains of their loved ones from such graves.

After Franco won the war in 1939, his dictatorship identified and paid tribute to his supporters who had lost their lives to the "red terror" exercised by the republican side.

The suffering of the anti-Francoists, however, was ignored. An estimated 30,000 Franco opponents killed in acts of repression during and after the war were left in unmarked mass graves.

After Franco's death in 1975, a democratic Spain wanting to leave the past behind granted an amnesty to his collaborators, and his human rights abuses were not widely discussed until Jose Luis Rodriguez Zapatero's Socialist government passed the so-called Law of Historic Memory in 2007.

The law seeks to restore the dignity of Franco's victims with measures such as the removal of Francoist monuments or some support to associations digging up remains from mass graves.

The law has been followed by a judicial initiative by National Court judge Baltasar Garzon to establish a census of Franco's victims, and to investigate what the magistrate sees as a systematic campaign to exterminate leftists and as a crime against humanity.

Garzon estimates that the Francoist repression killed more than 100,000 people, twice as many as are believed to have died in republican atrocities.

The total number of war victims is estimated at more than 500,000.

When Jesus Gutierrez' four uncles became "disappeared people," a status they still retain, their mother Maria became ill from grief. She, her husband and three daughters moved away from the village.

Jesus' father Severiano, who had stayed behind in Madrid when his brothers left on their fatal trip, was the only son to survive. He died in 1953 without finding out where Jose, Juan, Nicolas and Francisco were buried.

"I remember his sad smile when he talked about them," says Jesus, who feels he has a "debt" with his father to give his uncles dignified burials.

After several years of investigations, Gutierrez located the likely site of the mass grave.

He requested assistance from the Association for the Recovery of Historic Memory (ARMH), one among dozens of groups which have disinterred the bones of some 4,000 people from mass graves.

There was indeed a space underground, geo-radar revealed, in the terrain owned by the Catholic Church in an idyllic rural landscape.

But when Gutierrez sought permission to dig into the site, he met with silence.

"Nobody here knows anything yet" about a possible mass grave, village mayor Francisco Gonzalez Alvarez told dpa. He belongs to the conservative People's Party 
(PP), which opposes exhumations, arguing that delving into the Franco era reopens old wounds.

The local priest also does not want to discuss the affair. "I know nothing about it," says the cleric of the Catholic Church, which was one of the pillars of the Franco regime.

"We need to rescue history" from oblivion "so it does not repeat itself," says Gutierrez, who finally asked judge Garzon to order the opening of the mass grave.

Garzon has now authorized the opening of the grave in La Serna del Monte and 18 others, including one believed to contain the remains of poet Federico Garcia Lorca.

However, an appeal is pending against his investigation by prosecutors who argue that it lacks a legal basis.

Even if exhumations will go ahead on a large scale, experts see identifying and reburying all the victims as an impossible task. (dpa)