PONTIAC, Mich. (AP) — A teenager who killed four students at a Michigan school in 2021 was not mentally ill at the time and understood the tragic consequences of his actions, a psychiatrist testified Friday as prosecutors tried to bolster their argument that a life prison sentence fits the mass shooting.

“I can absolutely understand how it would be difficult to imagine how a sane person could commit mass murder,” said Dr. Lisa Anacker, who evaluates criminal defendants at a state psychiatric hospital. “But the research does show us that mental illness does not account for most of the violence in our country.”

She said Ethan Crumbley, who was 15 at the time, communicated clearly with police immediately after the Oxford High School shooting, followed commands and showed no signs of bizarre behavior.

A reference to “demons” in a video that he made on the eve of the shooting was a reference to his “idol,” a Florida school shooter, not himself, Anacker said.

“I asked the defendant if he was hallucinating at the time of the shooting. He told me he was not,” she testified.

Anacker appeared at the fourth and final day of a hearing to determine whether the teenager will get a life sentence. An immediate decision was not expected.

Crumbley, now 17, pleaded guilty to murder, terrorism and other crimes. Because of his age, he can’t automatically be given a life prison term. Oakland County Judge Kwame Rowe must consider his maturity, mental health, tumultuous family life and other factors set by the U.S. Supreme Court.

His attorneys are arguing that he can be rehabilitated while in prison and should receive a sentence giving him an opportunity for parole some day.

“Ethan’s brain is still maturing,” psychologist Colin King said on Aug. 1.

King said the shooter was like a “feral child” because of his home life and mentally ill when he attacked students and staff at Oxford High.

Rowe still can order a life sentence, but it would be rare for a Michigan teen. Crumbley otherwise would face a minimum prison sentence between 25 years and 40 years, followed by eligibility for parole.

James and Jennifer Crumbley are separately charged with involuntary manslaughter. They are accused of buying a gun for their son and ignoring his mental health.

During previous days of testimony, prosecutors focused on the chilling details of the crime. Ethan Crumbley had made a video, declaring in blunt words what he would do the next day at this school.

The judge listened to eyewitness accounts from four people, including a staff member who was wounded and a student who saved a wounded girl. Besides the deaths of four students, seven other people were shot.

There were opportunities to prevent the tragedy. No one checked the shooter’s backpack for a gun that day, although he was pulled into a meeting with his parents and school staff because of his violent drawings. He was allowed to remain in school.