Mexican authorities should allow international investigators to interview soldiers who may have witnessed the abduction and apparent massacre of 43 trainee teachers last year, a top United Nations official said on Wednesday.
The disappearance of the students in the southern town of Iguala and subsequent investigation into the attack has drawn sharp criticism of the government of President Enrique Pena Nieto for its inability to solve the case.
During a visit to the country, U.N. High Commissioner for Human Rights Zeid Ra'ad Al Hussein said Mexico's top military brass should allow a panel of experts from the Inter-American Commission on Human Rights (IACHR) to interview soldiers in the Iguala area at the time of the attack.
"It is important that the government acts decisively on the recommendations of the (IACHR panel), including its insistence that authorities reverse their decision to not allow the experts to interview members of the 27th Battalion," said Al Hussein, according to a Spanish-language translation of his remarks.
On Monday, Mexican Defense Minister Salvador Cienfuegos said he would not permit the panel to interrogate his troops, and rejected any suggestion they may have been involved.
In the months after the incident, the government sought to wrap up its investigation, declaring that a corrupt cadre of local police in cahoots with a drug gang confused the students for a rival gang. The government says they rounded up bodies and burned them on a pyre in a nearby town.
However, a panel of respected international investigators last month rejected the official account, pointing to suspicions of forced confessions and possible collusion by federal and state security forces, including the army.
Zeid also called on the Mexican government to set a timetable for withdrawing military personnel from law enforcement duties because military forces aren't designed to do police work.
It "has to be driven by a sense of real urgency, real urgency. It's not something that can wait endless months," he said.
Zeid said Mexico's defense secretary, Gen. Salvador Cienfuegos, had told him the army doesn't desire a policing role.
But Zeid added that better police forces have to be trained before Mexico's army withdraws or the military will leave a vacuum.
Mexican soldiers and marines began leading the fight against cartels after many police units proved too corrupt or inefficient to take them on.
But soldiers have been accused of human rights abuses, including a 2014 case in which three soldiers were charged with homicide in the slaying of at least eight suspects after they surrendered.