MONROE, Mich. (AP) — A southwestern Michigan middle school student is in custody after authorities say he took an inactive grenade to school and made threatening statements to other students.

The Monroe Police Department and the Monroe Public Schools say the student was lodged in a detention center Wednesday after a school resource officer found the grenade in the student’s locker. The device had been modified and was incapable of detonating.

Police say the student showed the device to other students and made the threatening statements. A student reported the incident to a teacher.