Mexico's attorney general said Thursday that people detained in the case of 43 missing students have identified more mass graves presumed to contain their bodies.
Jesus Murillo Karam said the number of people detained in the case is now 34.
Prosecutors attribute the Sept. 26 disappearances in the city of Iguala to the municipal police, who also killed six and wounded at least 25 in separate attacks.
Two weeks after 43 students disappeared in a clash with police in rural southern Mexico, dozens of anxious parents have gathered at a teachers college that was supposed to be their children's escape from life as subsistence farmers.
Wearing donated clothing, they waited for any word on the fate of their children, eating simple meals of rice, beans and tortillas and holding prayer sessions in a makeshift shelter on the school's covered courtyard.
"They took him away alive, and that's the way I want him back," said Macedonia Torres Romero, whose son Jose Luis is among the disappeared.
But it seems ever more unlikely as time passes.
The case has outraged Mexicans even in a country where abuse of authority is common in remote areas. Some of the detained led authorities last weekend to mass graves holding 28 bodies that some fear belong to the students. Their identities are still unknown.
That 43 young men went missing at the hands of the state has drawn calls from around the world for justice, including the U.S. State Department and the Organization of American States, where Secretary General Jose Miguel Insulza said all of Latin America is grieving.
Four more police officers have been arrested in the case, bringing the total to 26, state prosecutor Inaky Blanco announced Thursday. He also said he is asking the state congress to strip Iguala Mayor Jose Luis Abarca of the political immunity elected officials have under Mexican law. Abarca, who authorities say is on the run, may face charges as well for not intervening to stop the attacks.
The teachers college students and their families come mostly from the remote mountains of the southern state of Guerrero, where they live in poverty under the thumb of corrupt governments, drug traffickers or armed vigilantes, groups that have sprung up amid the region's lawlessness.
Graduates of the Rural Teachers College Raul Isidro Burgos, in the Ayotzinapa neighborhood of Tixtla, and others in the normal school system are guaranteed teaching jobs that pay just $500 a month at schools often reachable only on foot.
Ayotzinapa graduate Rogelio Guerrero Lopez now teaches in an impoverished three-room school in the mountains, four hours up dirt roads. Two weeks ago the teachers could not leave the school because a drug gang had blocked the road. He was afraid to name which one. Farm families in the area grow marijuana and opium poppies "to get a little money."
Despite the pervasive poverty and violence, Guerrero Lopez has convinced some local kids to attend Ayotzinapa. The college is free, and students are eager to work.
But they also become part of the fray. They are indoctrinated in leftist politics and justify their hijacking, stealing and civil disruptions in the name of spreading empowerment to Mexico's most impoverished, exploited citizens.
The face of Argentine revolutionary Ernesto "Che" Guevara stares down from the side of a building emblazoned with the slogan "I will return, and I will be millions." Other murals feature the likes of Marx, Lenin and Engels.
The teachers colleges began radicalizing in the 1960s, said Jorge Javier Romero, an education expert at the Autonomous Metropolitan University in Mexico City. Noted rural teacher and guerrilla leader Lucio Cabanas, who died in a shootout with Mexican troops in 1974, came out of Ayotzinapa.
Students are expected to go out on risky fundraising "activities" that range from passing the hat in town to taking over a highway tollbooth and letting motorists drive through in return for a "donation." It sometimes entails hijacking buses or food delivery trucks or blocking highways, and can lead to clashes with police.
On Sept. 26, Jose Luis joined in one of the activities, which apparently involved passing a tin can in the city of Iguala. He told his mother beforehand that he was afraid. So was she: "I told him, things can happen out there."
That was their last conversation.
Officials say municipal police opened fire on buses the students had hijacked to return to campus. Six people died, and dozens of students were taken away by police. One suspect told authorities they were turned over to a drug gang that killed at least 17 of them at a clandestine mass grave, where 28 burned and dismembered corpses were unearthed last weekend.
Back at Ayotzinapa, students kept to their daily routines this week following the grim discovery. Everyone pitched in to sweep out the patio, wash down its flagstones with buckets of water, air out bedding and scrub clothing in communal concrete basins.
The bustle contrasted with the silent sadness of the courtyard, where parents tried to hang on to hope.
"I'm staying here until I find out about my son," Torres said, tears welling in her eyes. "I'm not leaving here till then."
The Associated Press