Frequently left home alone, Ethan Crumbley texted his mother in March 2021 that he had seen a demon in their house, one that hurled dishes across the kitchen. Days later, his parents, James and Jennifer Crumbley, discussed how their teenage son was “worked up and agitated,” weighing whether to give him Xanax.
The next November, James Crumbley, ignoring what seemed like warning signs that Ethan had mental health issues, bought his son a semiautomatic handgun. Ethan, then 15, used the gun to kill four students at Oxford High School, the worst school shooting in Michigan history.
On Tuesday, Jennifer Crumbley, 45, is scheduled to go on trial, charged with involuntary manslaughter for the deaths — new territory when it comes to prosecuting school shootings. James Crumbley, 47, faces a separate trial, scheduled for March, also on involuntary manslaughter charges related to the killings.
Although adults have been prosecuted before when children commit violent crimes, the Oxford High School case goes a step further by trying to hold parents criminally liable for an intentional mass shooting. The Oakland County prosecutor, Karen D. McDonald, has said that the Crumbleys are culpable because they allowed their son access to a handgun while ignoring warnings that he was troubled.
Both parents have pleaded not guilty, and their lawyers have said that they had no inkling that Ethan was capable of such violence.
“One of the bedrock principles in American criminal law is that you’re not responsible for somebody else’s actions,” said Ekow N. Yankah, a professor at the University of Michigan Law School. But Mr. Yankah said the Crumbleys provided a perfect case to test that principle, pointing to what he called a “damning” set of facts against the couple.
“It’s hard to think of a set of facts that are more inviting for prosecution,” he said.
Extensive pretrial testimony and court documents have portrayed the couple as neglectful parents. They drank heavily, fought loudly in front of Ethan and frequently left him at home alone, despite his shaky mental health.
After James Crumbley purchased the gun, his wife took Ethan to the shooting range.
When a teacher reported seeing Ethan searching online for ammunition, his mother did not seem alarmed.
“LOL I’m not mad at you,” Jennifer Crumbley texted her son. “You have to learn not to get caught.”
On the day of the attack, after a teacher found Ethan with a violent drawing depicting a shooting, his parents declined a school counselor’s request that he be taken home.
After the arrest of their son, the Crumbleys appeared to flee to avoid prosecution and the police discovered them hiding in the basement of a Detroit art studio. (Lawyers for the parents said that the Crumbleys had not fled but rather left town for their own safety, and were planning to return for the arraignment.)
It is unclear whether Ethan, now 17, will be called to testify, but his lawyers said that they will advise him to invoke his right to remain silent. Ethan is appealing his life sentence without parole.
Unable to post a combined $1 million bail, the parents have been held in the Oakland County Jail for more than two years. Judge Cheryl A. Matthews of the Oakland County Circuit Court will preside over both trials, which will be held separately at the request of the couple.
Since the shooting on Nov. 30, 2021, Ms. McDonald, the prosecutor in affluent Oakland County, outside Detroit, has turned gun violence into a personal crusade. In an interview shortly after the shooting, Ms. McDonald said she viewed the attack as a chance to promote responsible gun ownership.
She also formed a commission to study ways to prevent gun violence. Partly spurred by the shooting, the Michigan Legislature recently passed a measure that requires gun owners to store their firearms in a locked container when a minor is likely to be on the premises. Ethan has said that the gun he used was not locked.
In 2000, Arthur Busch, a former prosecutor in nearby Flint, Mich., handled a school shooting case there. Kayla Rolland, a first grader in a suburb near Flint, was shot and killed by a 6-year-old classmate.
Prosecutors said that the boy, who found the gun in a home where he lived with relatives, treated the weapon as if it were a toy. His uncle, who was charged with involuntary manslaughter for leaving the gun accessible, pleaded no contest and spent two years and five months in prison before being released on probation.
Still, Mr. Busch said, the Crumbley case could be hard to prosecute.
“The fact that they bought him a gun when he had these profound mental health problems, that’s pretty reckless,” Mr. Busch said. “But the closer the public begins to look at this, I think there are parents who could say: ‘That could be me. I have this insolent, oppositional child and I get to be liable for that? That doesn’t seem fair to me.’”