DETROIT, Mich. (AP) — A teenager accused of killing four fellow students and injuring more at a Michigan high school is expected to plead guilty next week, authorities said Friday.

Ethan Crumbley had created images of violence during a classroom assignment last November but was not sent home from Oxford High School in southeastern Michigan. He pulled out a gun a few hours later and committed a mass shooting.

“We can confirm that the shooter is expected to plead guilty to all 24 charges, including terrorism and the prosecutor has notified the victims,” said David Williams, chief assistant prosecutor in Oakland County.

Crumbley, 16, is due in court Monday.

He was 15 when the shooting occurred. Crumbley’s parents were summoned to school that day to discuss their son’s ominous writings. A teacher had found a drawing with a gun pointing at the words, “The thoughts won’t stop. Help me.”

James and Jennifer Crumbley had said they would get him counseling but declined to take Ethan home, according to investigators.

Oxford High is roughly 30 miles (50 kilometers) north of Detroit.