MEXICO CITY (AP) — Mexican authorities have arrested three more suspects in the disappearance of 43 students more than a year ago in a southern state.

National security commissioner Renato Sales says the suspects belong to an organized crime group that authorities say received the students after they were taken by police in Iguala, Guerrero state.

Six other people were killed the night of Sept. 26, 2014, including 22-year-old student Julio Cesar Mondragon.

Sales said Friday at a news conference that one of the arrested is considered the prime suspect in Mondragon's death. Authorities have arrested 113 people in the disappearances, including the ex-mayor of Iguala.

Government investigators have said that police handed the Ayotzinapa teachers' college students over to members of the Guerreros Unidos cartel. The search continues for the students.