ST. GEORGE, Utah (AP) — A southern Utah teenager accused of trying to set off a homemade bomb at his high school will remain in juvenile detention pending his preliminary hearing in May on attempted murder and other charges.

Judge Paul Dame ruled during a juvenile hearing in St. George on Wednesday that the 16-year-old boy poses too big of threat to public safety to be released before the May 11 hearing.

No explosion resulted and no one was hurt March 5 after a backpack with the explosive device was found emitting smoke in a common area of Pine View High School.

He’s also charged with misdemeanor graffiti and abuse of a flag for allegedly cutting up an American flag and spray-painting words including “ISIS” on a wall at a different high school in nearby Hurricane.