The former mayor of the southern Mexican city of Iguala has been charged with murder and attempted murder in connection to the disappearance of 43 student-teachers in September.

On Friday, prosecutors in Guerrero, Mexico, announced that they have formally charged Jose Luis Abarca with "aggravated homicide against six people" and the "attempted murder of others," reads a statement on their website, according to BuzzFeed.

The six people died when local police opened fire on Sept. 26 in an attack directed at 43 students who attended a rural teacher-training college. According to authorities, Abarca ordered police and a gang to attack the students in order to prevent them from derailing a speech set to be delivered by his wife, reports the Los Angeles Times. 

"He didn't say that they should be kidnapped and killed," the Attorney General Jesús Murillo Karam said. "But the order makes it clear that they [the police] should act in that way."

After the police shooting, the surviving students were then rounded up by members of the local drug-trafficking gang, Guerreros Unidos, which reportedly had ties with the former mayor. The gang then burned the victims on a pyre and pulverized their teeth and bones to prevent them from being identified. Although officials have not confirmed that the human remains belong to the missing students, Karam stated that there are "many indications" that the victims were the students, the Guardian reported.

So far, around 74 people have been arrested in connection with the disappearances and deaths of the students, reports CNN.

Earlier this week, Mexican officials announced that gang members and police officers confessed to participating in the killing of the students on Sept. 26.

"These killings and forced disappearances reflect a much broader pattern of abuse and are largely the consequence of the longstanding failure of Mexican authorities to address the problem," Human Rights Watch Americas Director José Miguel Vivanco said.