A US teenager charged with killing four pupils at a Michigan high school will pursue an insanity defence, his lawyers said in a notice filed on Thursday as he, his parents and school officials faced a new lawsuit over the attack at Oxford High School.
The notice, listed in a summary of case filings, should lead to mental health exams of 15-year-old Ethan Crumbley, who is being charged as an adult with murder and other crimes in the shooting, which also wounded six other pupils and a teacher.
Experts will consider whether the teenager understood the wrongfulness of his conduct on the day of the shooting.
The lawsuit, meanwhile, was announced on behalf of the parents of Tate Myre, who was killed on November 30, and other pupils who witnessed the shootings. It alleges negligence by school officials and Ethan's parents over the attack.
“We’re sad and heart-broken — our lives forever changed,” William Myre, Tate's father, said at a news conference.
“Our family will never be the same. We’re not doing good. All we do is walk around the house and think about Tate. We think about him every day.”
The lawsuit, which seeks at least $25,000, names Oxford High School’s dean, two counsellors and three teachers. Ethan and his parents also are named as accused.
The suspect’s parents are accused of intentional, reckless and negligent conduct that led to the mass shooting. The Oxford High School staff and teachers are accused of gross negligence that led to the shooting by not removing the shooter from the school building earlier.
Ethan is being held in the Oakland County Jail.
The notice filed on Thursday by his lawyers will lead to exams by the state Centre for Forensic Psychiatry and experts retained by the defence and the prosecutor’s office.
Under Michigan law, if someone is found not guilty by reason of insanity, they do not walk free. They must be referred to a state psychiatric centre for custody and further evaluation.
Someone who is found guilty but mentally ill still would be sentenced to prison but with recommendations that they receive treatment.
The day of the shooting, a teacher found a note on Ethan's desk and took a photo. It was a drawing of a gun pointing at the words, “The thoughts won’t stop. Help me.”
The gun used in the shooting was bought days before by Mr Crumbley and Ethan had full access to it, authorities said.
The Crumbleys were later charged with involuntary manslaughter.
Detroit-area lawyer Ven Johnson, who is representing the families in the lawsuit filed on Thursday, said Ethan knew what he was doing and “clearly he was disturbed”, but his parents did nothing.
Chad Gregory recounted during Thursday’s news conference what his son, Keegan, witnessed during the shooting.
Keegan was texting his family from a bathroom stall where he and another pupil were hiding.
“He was in that bathroom for five minutes,” Mr Gregory said. “He was in there with a shooter who had just killed, wounded, injured. [The other pupil] Justin gave him a plan that ‘if we get a chance, we will run.’”
The school, in Oakland County, is about 50 kilometres north of Detroit. It reopened Monday with its interior renovated since the shooting.