MEXICO CITY — The former police chief of Iguala, where 43 students went missing in 2014, was detained Friday after two years at large in a development that Mexican authorities hope could shed new light on the disappearances.

The National Security Commission announced that federal agents arrested Felipe Flores in Iguala, in the southern state of Guerrero, in the morning.

Attorney General Arely Gomez tweeted that the detention “will allow the collection of key testimony to clarify the facts of Iguala.”

The students from the teacher’s college at Ayotzinapa were taken by police in Iguala on Sept. 26, 2014, and have not been heard from since.

Prosecutors say they were handed over to a drug gang, killed and incinerated in a massive fire at a trash dump. But independent experts who reviewed evidence in the case have cast into doubt the contention that the students’ bodies were burned, and the victims’ families continue to vocally demand more answers.

Authorities had arrested 128 people. Seventy of those, mostly police officers and alleged cartel members, are currently being prosecuted. A number of them have alleged torture by officials and it is unclear how that will affect their cases. But Flores could provide a break or at least a new perspective on how events unfolded that night.

“We hope that the arrest of this person leads to some good news for us,” said Felipe de la Cruz, a spokesman for the families. “We hope that what he says takes us definitively toward the truth and to where the youths are, because that’s what we’ve looked for all this time.”

The disappearances and authorities’ inability to conclusively clear up what happened to the students have been an embarrassment for the government of President Enrique Pena Nieto.