Felipe Flores, the former police chief of Iguala, where 43 students disappeared in 2014, has been detained after two years on the run, Mexican officials announce.
He was arrested in Iguala, in the southern state of Guerrero, where the incident happened.
Mexican government says the students were arrested by police before being handed over to a drugs cartel who killed them and incinerated their bodies.
Families and independent experts contest this claim.
The panel of experts, working for the Inter-American Commission on Human Rights, said the account that the students had been burnt beyond identification at a rubbish dump was physically impossible.
Felipe Flores was police chief of Iguala when the incident took place on September 26, 2014, and his arrest may offer new clues as to what exactly happened then.
Attorney General Arely Gomez welcomed Felipe Flores’ capture, tweeting that it would allow investigators to get “a fundamental statement to clear up the events”.
The case has tainted Mexican President Enrique Pena Nieto’s image.
VIDEO Mexico is reopening the investigation into last year’s disappearance of 43 students in the state of Guerrero.
An international panel of experts had said the investigation was flawed.
The students’ families have disputed the government’s account of what happened in September 2014.
The Mexican government says that police in the town of Iguala handed the students over to a drugs cartel who killed them and incinerated the bodies.
The panel of experts, working for the Inter-American Commission on Human Rights, criticized the government’s version of events.
It concluded that the government’s account that the students were burnt beyond identification at a rubbish dump was physically impossible.
The panel said official reports appeared to downplay the presence of federal police and troops near the areas where the students were seized.
The experts said the army had refused to allow them to interview soldiers.
They came up with a list of 10 recommendations which the Mexican government has agreed to abide by.
Among them, the search for the students will be re-launched following outlines laid down by the experts and carried out in coordination with the victims’ families.
The experts also want the report they published to form part of the government investigation – following up recommendations and evaluating issues that arose from the report.
Further ten municipal police officers have been arrested by Mexican authorities investigating the disappearance of 43 student teachers in Guerrero state.
Around 90 people in total, including 58 police officer, have been detained so far.
The students disappeared in September 2014 after clashes with police in the city of Iguala.
National prosecutors say police handed them to criminal gangs who murdered them and burnt their bodies.
Parents of the students dispute this, arguing the authorities are hiding what happened to them.
The remains of only one student, Alexander Mora, have been identified so far.
They were found near a rubbish dump where criminal gang members say the students were taken to be shot and their bodies burnt.
Members of the gang said they killed the 43 and burned their bodies after they were told the students belonged to a rival gang.
The relatives of the other 42 missing students say they will not give up hope of finding them alive until forensic evidence proves they are dead.
The slow pace of the initial investigation into their disappearance and the collusion it has highlighted between local authorities and drug gangs has led to mass protests across Mexico.