The attack killed three children and a teacher. The shooter also died after a Bend resident followed him into the school and shot him, according to information released about the incident.

People close to the investigation say the boy’s mother, Shauntai Nickerson, bought the Mossberg Maverick 88 pump-action shotgun used in the shooting. Investigators have not publicly explained how her son got access to it. Nickerson previously told other reporters she was sorry for the families’ losses and would have acted to prevent the shooting if she could. She did not respond to a request for comment.

Whether prosecutors could charge her is uncertain. Shawn Kollie, a Medford attorney who specializes in firearm law, said a case would likely depend on evidence that a parent knew the child posed a danger and disregarded that risk. Such evidence can be difficult to establish, he said.

“For criminal liability to attach, there has to be some evidence that this person means to do people harm,” Kollie said.

Police have not disclosed a motive or identified social media posts by the teen in the weeks before the shooting. He had previously attended Silver Rail.

Oregon requires gun owners to securely store firearms in their homes. Under state law, an owner can face increased fines if a minor gains unauthorized access to a firearm. The state also allows courts to temporarily remove firearms from people found to pose a danger to themselves or others.

The case may be weighed against a small number of prosecutions elsewhere. In Michigan, Jennifer and James Crumbley were convicted of involuntary manslaughter after their son killed four students at Oxford High School in 2021. They each received 15-year prison sentences and may be eligible for parole after serving 10 years.

Oakland County Prosecutor Karen McDonald said the prosecution focused on showing that the parents understood the danger their son posed with a firearm and failed to respond. But she cautioned that charging parents should be reserved for the most egregious cases.

In Georgia, the father of the Apalachee High School shooter was convicted of second-degree murder and involuntary manslaughter. Prosecutors said he had bought his son a rifle despite a police investigation into threats about a school shooting.

Oregon’s gun laws include restrictions on bump stocks and so-called ghost guns. But Measure 114, approved by a majority of voters in 2022, has not taken effect amid court challenges. It would restrict high-capacity magazines and require safety training, background checks and permits for firearm purchases. The Oregon Supreme Court is considering the measure.

Amie Wexler of the Oregon Alliance for Gun Safety said Oregon’s laws remain weaker than those in Washington and California. She also said Measure 114 would not have prevented the Bend shooting because the shotgun used did not have a high-capacity magazine.