Mexican federal forces disarmed a southern city’s entire police corps and took over security Monday after officers were accused of colluding with a gang in violence that left 43 students missing.
The deployment in Iguala, 200 kilometers (125 miles) south of Mexico City, came after President Enrique Pena Nieto pledged justice in a case that has challenged his vow to tame crime in his country.
Authorities discovered a mass grave on a hill outside Iguala over the weekend containing 28 unidentified bodies, raising fears over the fate of the students, who were last seen in the city more than a week ago.
Authorities say it will take at least two weeks to get the results of DNA tests to identify the corpses. Some bodies were in pieces after being set on fire in a bed of branches.
Witnesses say several students, who are from a teacher training college known as a hotbed of radical protests, were whisked away in police vehicles on the night of September 26 after officers shot at buses the youngsters had commandeered to return home.
Prosecutors say the Guerreros Unidos drug gang participated in the night of violence that left six people dead, 25 wounded and 43 missing.
Two hitmen have confessed to killing 17 of the 43 students, saying they were told by a police commander to head to the scene of the shootings, while a gang leader told them to execute the youths, authorities said.
The government said its new federal police unit, the paramilitary-like gendarmerie, took charge of security Monday.