The father of a 15-year-old Michigan school gunman who killed four students has been convicted of manslaughter.
The trial heard that James Crumbley, 47, had ignored his son Ethan's mental health needs, buying him the handgun he used in the November 2021 attack.
He and his wife - who was convicted on the same charges - now both face a maximum of 15 years in prison.
The case is thought to mark the first time the parents of a mass shooter have been held criminally liable.
The couple are scheduled to be sentenced on 9 April.
The jury deliberated for just over a day after a nearly week-long trial. James Crumbley was in court on Thursday evening for the verdict and appeared to show little reaction as it was read out.
Their son killed fellow students Tate Myre, 16; Hana St Juliana, 14; Madisyn Baldwin, 17, and Justin Shilling, 17, with a semi-automatic handgun at Oxford High School. Seven others were also injured in the shooting.
He is serving a sentence of life in prison without parole.
Steve St Juliana, Hana's father, said on Thursday evening that the prosecution of the Crumbleys was "just the beginning steps" when it came to dealing with gun violence in the US.
"Our children are dying on a daily basis in mass murders and we do very little about this," he added.
"We can put people on the Moon, we can build skyscrapers, huge monuments like the Hoover Dam and we can't keep our kids safe in schools."
In a statement, attorney Ven Johnson said that James and Jennifer Crumbley played a "causal role" in the deaths of the four students.
"This guilty verdict...won't bring back the lives of these four students, but it represents one more step towards holding everyone responsible under the law," Mr Johnson said.
Earlier this week in her closing arguments to the jury of six men and six women, prosecutor Karen McDonald called the attack "preventable and foreseeable".
She added that James Crumbley's actions had been "rare and egregious".
He did not take even the slightest measures to ensure his son was not a threat after giving him a semi-automatic pistol as a gift just days before the shooting, said the prosecutor.
Prosecutors also said the Crumbleys had not done enough to address their son's declining mental health.
On the morning of the shooting, the two parents cut short a school meeting about a disturbing drawing their son had made to go to work and had declined to take him home.
School officials sent him back to class without checking his backpack, which contained a gun.
When Crumbley heard about the shooting, he rushed home from his job as a DoorDash delivery driver, looking for the weapon, the trial heard.
Crumbley's defence lawyer, Mariell Lehman, argued that "James had no idea that his son was having a hard time".
Crumbley did not testify, unlike his wife, who took the stand during her trial and tried to blame her husband.
Prosecutors said the Crumbleys had also failed to ensure the weapon was safely stored.
"Parents and gun owners have a responsibility to prevent children from accessing deadly weapons," said Nick Suplina, with the advocacy group Everytown for Gun Safety, in a statement, adding the verdict "further underscores this critical duty of responsible gun ownership".
The Crumbleys were charged by police within days of the killings.
Initially, the parents were supposed to be tried together but in November sought separate trials.
