Riot-equipped officers of the Mexican federal police attacked students ( normalistas ) from the Ayotzinapa teachers college and members of a dissident teachers union in the capital of Guerrero on Sunday. There were 18 reported injuries, 13 of them protesters. Two professors were badly beaten.

An account of the violence in the Mexico City periodical Proceso indicates that it was triggered when five officers in the Federal Police ( Policía Federal ), reportedly drunk and dressed as civilians, were returning to police headquarters at a local hotel in Chipancingo. Angered by barriers that had been set up in preparation for an arts and music festival, the officers initiated a confrontation with the normalistas and members of the Cordinadora Estatal de Trabajadores de Educación de Guerrero (CETEG Guerrero State Education Workers Coordinating Committee).

The “a candle in the dark” ( una luz en la oscuridad ) festival was part of protests over the disappearance and likely murder of 43 normalistas in September.

Based on interviews with eyewitnesses, Proceso reports that the police fled into the hotel after striking some of the protesters. Incensed, the protesters rallied at the entrance and demanded that the police not interfere with their concert.

It was then that a squad of police dressed in riot gear attacked the crowd. A street battle ensued, as other normalistas, parents of the disappeared students and CETEG members arrived. The battles continued until dawn. In a negotiated settlement, the students and teachers agreed to release three police officers they held in return for the release of two CETEG members that the police had captured.

Some CETEG members reportedly went to the police training center in Chipancingo and set fire to police vehicles and tried to storm the guardhouse.

Guerrero’s acting governor placed the blame entirely on the students. He accused them of having entered the hotel looking for a fight.

The confrontation in Chipancingo is indicative of the tensions that exist in Guerrero and throughout Mexico. There is growing anger over the fact that there has yet to be a clear explanation of what has happened to the 43 students.

The official explanation given by the Peña Nieto administration is that a corrupt local mayor in the city of Iguala and the local police force were entirely responsible for the attack the Ayotzinapa normalistas, handing them over to the drug gang, Guerreros Unidos. This, however, is a self-serving cover-up.

An investigation by Proceso, with the support of UC Berkeley’s Investigative Reporting Program, has uncovered documents exposing the role of the federal police and the military in the abduction and massacre of the of the students.

One of the most damning documents, from October, is a report sent to the Peña Nieto administration. The document makes clear that the normalistas were being watched by federal and state police from the time they left Ayotzinapa at 6:00 pm on the day of the massacre.

At 8:00 pm, both federal and state police officers had reached the spot on the Iguala-Chipancingo highway were the students were campaigning for funds. At 9:22 pm, the federal police commander was informed that the students had moved on to the Iguala bus station. At 9:40 pm, the Chipancingo Communications and Control Center received news that the massacre had begun.

The Proceso report points to a possible motive for targeting the students: opposition within the teachers college to the education policies of the government. Successive governments have attacked the rural normal schools (associated with the education policy of Lázaro Cárdenas (1934-1940)) as part of an overall attack on the working class.

Out of the 46 rural teaching colleges that existed in the 1930s, only 12 exist today.

Normal schools receive roughly three dollars per day from the federal government to feed their live-in students. As a result, students are forced to raise funds from their surrounding communities.

The assault and massacre of the students from the Raúl Isidro Burgos Normal School in Ayotzinapa took place in the context of an overall assault on public education in México. “Reforms” under the administration of Enrique Peña Nieto make a mockery of the constitutional guarantee to free public and secular education.

Amidst deep popular anger over the disappearance of the normalistas, fueled by growing social inequality and the right-wing policies of the government, there are signs that sections of the Mexican ruling class are looking toward authoritarian, military, solutions. That prospect was raised on December 10 when Navy Secretary Vidal Soberón declared that “outside forces” were manipulating the protest movement. Human rights activists in Guerrero are being investigated for possible connections with “subversives.”

Last month, General Salvador Cienfuegos, Peña Nieto’s defense secretary, warned ominously that the Army “acts with strength and determination when it becomes necessary,” in order to confront “instability” and “insecurity.”