A Mexican judge issued an arrest warrant for Tomas Zerón, the former head of investigations for the Attorney General’s Office, and five other former officials on Wednesday for alleged violations in the investigation of the case of 43 college students who disappeared in 2014.

In 2014, 43 college students were seized by police in southern Guerrero state. Although DNA testing only successfully identified one missing student from the evidence, Mexican officials presumed in 2015 that all 43 were dead. The investigation was widely criticized, and the current administration pledged to re-open the case.

Zerón oversaw the criminal investigation agency of the Attorney General’s Office, and he was responsible for overseeing the forensic work of the case. 

Six former officials, including Zerón, face charges that include torture, forced disappearance, and judicial misconduct.

Three of the officials have been arrested, while Zerón and two others remain at large. Interpol was notified, in the event that Zerón is outside of Mexico. There were some indications that he may have left for Canada in 2019.