The Michigan high school shooting suspect's lawyers filed court papers saying he'll try to use insanity as a defense

• The lawyers of the Oxford school shooting suspect filed court papers to pursue an insanity defense.
• The notice was filed on Thursday in Oakland County's 6th Circuit Court in Michigan.

The attorneys of the teen who authorities said shot dead four students and injured several more at a Michigan high school in November filed court papers saying he'll use insanity as a defense.

The 15-year-old was arrested after the rampage at Oxford High School and faces trial as an adult with four counts of first-degree murder and a terrorism charge.

The Notice of Insanity Defense was filed on Thursday in Oakland County's Sixth Circuit Court and should lead to a mental examination of the teen, according to court documents Insider reviewed.

An order has been submitted for an examination at Michigan's Center for Forensic Psychiatry, which could take a few months, a defense attorney for the teen told Insider.

"It would have been a mistake to not explore it — he's 15 years of age and obviously the charges couldn't be more serious," the attorney said. "So I think it's important that we just take a look to see what was going on with him at the time of the alleged offense."

According to an excerpt from Michigan's Code of Criminal Procedure, an individual is legally insane if "that person lacks substantial capacity either to appreciate the nature and quality or the wrongfulness of his or her conduct or to conform his or her conduct to the requirements of the law."

Michigan law states that the term "legally insane" applies only under specific mental health codes that define mental illness or intellectual disability.

"Mental illness or having an intellectual disability does not otherwise constitute a defense of legal insanity," the law reads.

The teen's parents were charged with four counts each of involuntary manslaughter in connection to the shooting.

Prosecutors have said that the teen's father purchased the handgun used in the shooting as an early Christmas gift, and that both parents ignored suspicious signs ahead of the shooting.