Missing Mexico students
Activists take part during a march to demand justice for the 43 missing students from Ayotzinapa Teacher Training in Mexico City on Dec. 26, 2014. Reuters/Bernardo Montoya

Maria de los Angeles Pineda, wife of a former mayor in Mexico, where 43 students went missing, was charged with organized crime and money laundering, prosecutors said Monday. The police force, which colluded with the mayor, had allegedly turned over the students to a drug gang, which killed them.

Prosecutors said that Pineda’s brothers were leading members of the Guerreros Unidos drug gang, according to The Associated Press. Pineda’s husband, Jose Luis Abarca, former mayor of Iguala, in the southern Mexican state of Guerrero, was earlier charged with organized crime, kidnapping and homicide in November, for events before the students' disappearance. Abarca and Pineda, who were arrested on Nov. 4, were being held under a provisional arrest until now.

A Mexican judge issued a warrant for Pineda’s pretrial detention "for her likely role in committing organized crime ... and operations with funds of illicit origin," Tomas Zeron, who leads the criminal investigation unit of the prosecutor's office, said, according to Agence France-Presse (AFP).

The students went missing on Sept. 26 and were later thought to be massacred by a police-backed gang, AFP reported. The allegations led to nationwide protests, with many protesters calling for President Enrique Pena Nieto's resignation.

In December, authorities confirmed that the DNA of one of the 43 missing students matched with a bone fragment that was found in a pile of remains in Cocula, a town in Guerrero state. Authorities had also found bags of ashes and remains at the site.

Jesus Morillo, the attorney general, had also said that most likely Abarca ordered police to go after the students, fearing they would disrupt Pineda's speech, according to local media reports. The police shot the students and killed three of them. After this, they handed over the rest to the drug gang, which burned them and threw their remains into a nearby river.

Mexico's gang-related violence has racked up a death toll of more than 100,000 people since 2007, Reuters estimated.