Pontiac, Michigan - A jury on Tuesday found a Michigan mother guilty of manslaughter over a school mass shooting carried out by her teenage son in an unprecedented and closely watched case.

Jennifer Crumbley (45) and her husband James (47) are the first parents of a school shooter to face felony manslaughter charges in the United States for the actions of their child.

Jennifer Crumbley was convicted of all four counts of involuntary manslaughter facing her after a jury in Pontiac, Michigan, deliberated for about a day and a half.

She is to be sentenced on April 9 and could face up to 15 years in prison. Her husband is to be tried separately in March.

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Ethan Crumbley, their 17-year-old son, is serving a life sentence for the November 30, 2021, shooting at Oxford High School, which left four students dead. The Crumbleys bought their son the 9mm SIG Sauer handgun he used to carry out the attack and were accused of ignoring warnings that he had mental health struggles.

In closing arguments, prosecutor Karen McDonald told the jury that Jennifer Crumbley failed to "exercise ordinary care when the smallest, tragically simple thing could have prevented it."

"She could have locked the ammunition. She could have locked the gun," McDonald said. "She could have told the school they had just gifted him a gun. She could have told the school about her son being in crisis previously and asking for help."

Defense attorney Shannon Smith countered that Crumbley cannot be held accountable for the actions of her son.

"No one could have expected this," Smith said. "Can every parent really be responsible for everything their children do?"

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"This case is a very dangerous one for parents out there," she added.

Crumbley testified during her trial that her husband bought their son the gun just days before the attack as an early Christmas present, and she took the boy to a shooting range the next day. She said her husband was responsible for storing the weapon at their home, and it was for her son "to use at the shooting range only."

She said she never had reason to believe her son was capable of carrying out such a violent act.

"I wish he would have killed us instead," she said.

The Crumbleys were summoned to the school on the day of the shooting after a teacher was "alarmed" by a violent drawing she found on Ethan's desk. The parents were shown the drawing and advised they needed to get the boy into counseling. They allegedly resisted taking their son home, and he returned to class. He later entered a bathroom, emerged with the gun which had been concealed in his backpack, and fired more than 30 shots.

Amid a huge number of deadly firearms incidents involving young people, pressure has been mounting in the US to punish parents who make it possible for their children to get weapons.

The father of an Illinois man accused of killing seven people in July 2022 pleaded guilty in November to misdemeanor charges of "reckless conduct" for helping his son obtain the assault rifle used in the mass shooting.

A Virginia woman whose six-year-old son shot and severely wounded his teacher was recently sentenced to two years in prison for felony child neglect and 21 months in prison after pleading guilty to illegally obtaining the firearm.