Germán Reyes was arrested on charges of homicide for the killing of Alejandro Arcos just a week after he took office as mayor, officials said.

Mexican law enforcement announced on Tuesday the arrest of a top municipal security official for the assassination of the mayor of the capital of the violence-plagued state of Guerrero. The murder and decapitation of Chilpancingo Mayor Alejandro Arcos shocked the country,

Authorities believe that Germán Reyes, a former prosecutor in Guerrero, worked in collusion with one of the two main gangs in the state to commit the crime

Mayor Alejandro Arcos Catalán was killed less than a week after taking office in Chilpancingo. On Tuesday, the authorities arrested the city’s public security minister in connection with his death.