MEXICO CITY >> Two detectives looking for 43 students who went missing almost ten years ago have themselves disappeared in Mexico’s Pacific coast state of Guerrero, Mexico’s president said Tuesday.

President Andrés Manuel López Obrador said that a search effort has been launched to find the two federal detectives, a man and a woman. Speaking at his daily news briefing, López Obrador said “I hope this is not related to those who do not want us to find the youths.”

The disappearances were the latest sign of what appeared to be a generalized breakdown in law and order in Guerrero state, home to the resort of Acapulco. The state has been dogged for a decade by the case of 43 students from a rural teachers’ college in Guerrero who disappeared in 2014 and are believed to have been abducted by local officials and turned over to a drug gang to be killed.

Students at that college, located in Tixtla, north of Acapulco, have a long history of demonstrating and clashing with police, an d last week a student was shot to death in what police said was a confrontation with students riding in a stolen car.

One of the police officers involved in that shooting had been detained and placed under investigation in the case, after the president described the shooting as “an abuse of authority” and confirmed the dead student had not fired any gun.

But López Obrador acknowledged Tuesday that the state police officer detained in the case had escaped from state custody before being turned over to federal prosecutors.

The president suggested that Guerrero state police had not properly guarded their colleague, saying arrest “protocols had not been followed.”

Adding to the confusion, the state prosecutors’ office denied Tuesday that the officer had ever been in custody.

And there was little evidence that the president’s pledges to investigate last week’s shooting — or the fate of the missing 43 — would placate the students’ traditionally violent protests.

On Tuesday, students demonstrators broke into state prosecutors’ offices in Chilpancingo, the capital of Guerrero state, set off explosives and burned 11 police patrol vehicles. The prosecutors’ office said four of its employees were injured in the attack.

The 43 missing male students are believed to have been killed and burned by drug gang members. The two missing detectives were part of a years-long effort to find where the students remains had been dumped. López Obrador did not specify when the detectives disappeared.

Authorities have been able to identify burned bone fragments of only three of the 43 missing students. The work largely involves searching for clandestine body dumping grounds in rural, isolated parts of the state where drug cartels are active.

So dominant are the drug cartels in Guerrero that videos posted on social media this week showed drug gang enforcers brutally beating bus drivers in Acapulco for failing to act as lookouts for the cartel.

One video showed a presumed gang enforcer dealing more than a dozen hard, open-hand slaps to a driver and calling him an “animal,” and demanding he check in several times a day with the gang.

In testimony before a U.S. Senate Intelligence Committee this week, the U.S. Director of National Intelligence, Avril Haines, acknowledged “there are parts of the country that are effectively under the control of the cartels in certain respects.”

The escape of the accused police officer and the disappearance of the two detectives came as tensions flared between López Obrador and the families of the missing students, who accuse him of not doing enough to investigate the fate of their sons.

Last week, protesters supporting the missing students’ families used a commandeered pickup truck to ram down the wooden doors of Mexico City’s National Palace, where López Obrador lives and works.

The protesters battered down the doors and entered the colonial-era palace before they were driven off by security agents.

López Obrador called the protests a provocation, and claimed the demonstrators had sledgehammers, powerful slingshots and blowtorches. López Obrador has complained about the involvement of human rights groups, who he claimed have prevented him from speaking directly to the parents of the missing students.