A teenager accused of killing four fellow students and wounding seven others at a Michigan high school is expected to plead guilty to murder this week, according to prosecutors. Ethan Crumbley had created images of violence during a classroom assignment last November but was not sent home from Oxford High School in southeast Michigan. He pulled out a gun a few hours later and committed a mass shooting, authorities said.

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

The 16-year-old suspect is due in court Monday. He was 15 when the shooting occurred at Oxford High, which is roughly 30 miles north of Detroit.

His parents had been 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.”

The teenager is charged with one count of terrorism causing death, four counts of first-degree murder, seven counts of attempted murder and 12 counts related to use of a gun. A first-degree murder conviction typically brings an automatic life sentence in Michigan. But teenagers are entitled to a hearing where their lawyer can argue for a shorter term.

James and Jennifer Crumbley had said they would get him counseling but declined to take him home from school that day, according to investigators. The parents are facing involuntary manslaughter charges, a rare case of prosecutors trying to make parents responsible for a school shooting. They are accused of making a gun accessible to their son and ignoring his need for mental health treatment, and were also due in court this week.

“Put simply, they created an environment in which their son’s violent tendencies flourished. They were aware their son was troubled, and then they bought him a gun,” prosecutors said in a court filing.

The parents said they were unaware of their son’s plan. They also dispute that the gun was easy to get at home.

Madisyn Baldwin, Tate Myre, Hana St. Juliana and Justin Shilling were killed, while six students and a teacher were injured.

In court documents, prosecutors have revealed portions of the suspected gunman’s personal journal. He said his grades were poor and that his parents hated each other and had no money.

“This just furthers my desire to shoot up the school or do something else,” the teen wrote.

The parents and their son are being held at the Oakland County jail, though the suspected gunman is kept away from adults.

Ven Johnson, an attorney who is suing the Oxford school district, said parents of the shooting victims would withhold comment until after the court hearing.