CHINO VALLEY, Ariz. — Authorities say they have questioned a 16-year-old boy accused of threatening to shoot up his former high school in a small Arizona town, and referred him for a mental health evaluation and treatment.

Chino Valley police say students told school officials about the potential threat at 8:50 a.m. Wednesday, leading authorities to place an officer at the school all day.

An officer also was placed at the teen’s current school in Prescott, where he was detained. He had no weapons on him.

Lt. Vincent Schaan says the teen told authorities he jokingly made statements to other students more than a month ago about opening fire at the school.

Authorities also interviewed the teen’s ex-girlfriend. Police say she received messages from him Tuesday that led some to believe an attack would occur at 2 p.m. Wednesday.