Collin Gray, the father of Georgia school shooter Colt Gray, was found guilty of murder and manslaughter on Tuesday in a case that will test the limits of what a mass shooter can do.

After deliberating for less than two hours, the jury found him guilty on all 27 charges: two counts of second-degree murder, two counts of manslaughter, 18 counts of child abuse and five counts of reckless conduct.

In the defense box, Colin Gray did not visibly react to the sentence. He was led out of the courtroom in handcuffs. He faces 10 to 30 years in prison for each murder charge and one to 10 years in prison for manslaughter.

Prosecutors accused Gray of buying his son an AR-15-style rifle as a Christmas present and allowing his son to obtain the weapon and ammunition despite warnings that it was a danger to others. On September 4, 2024, 14-year-old Colt Gray used the rifle to open fire at Apalachee High School in Winder, Georgia, killing two teachers and two students and injuring nine others.

“This man and his son are responsible for the immeasurable suffering that occurred on September 4,” prosecutor Patricia Brooks said in closing arguments. “They have blood on their hands.”

But Colin Gray’s defense claimed he had no knowledge of his son’s violent plans and had taken steps to get him to address his mental health issues.

The indictment alleges his actions amounted to “criminal negligence” due to “a conscious disregard for a significant and unreasonable risk.”

The trial was part of a broader effort to hold more people accountable, including the parents of the school shooter and the law enforcement officers who responded. The case is very similar to the 2021 trial of James and Jennifer Crumbley, whose 15-year-old son killed four students at a high school in Oxford, Michigan. They were each found guilty of manslaughter and sentenced to 10 to 15 years in prison.

Speaking after the verdict, Barrow County District Attorney Brad Smith noted that the Crumbley case set a precedent and said he hoped the ruling would “move things a little further.” And he refuted concerns that Colin Gray was being punished for his childish actions.

“This was a trial about the actions, choices and responsibilities of this defendant,” Smith said.

Authorities said the suspect, Colt Gray, admitted to the shooting. Now 16, he has pleaded not guilty to 55 felonies, including four counts of malice murder. A trial date has not been set.

The state filed a nearly two-week lawsuit that included emotional testimony from students and teachers who survived the shooting, police interviews with Collin Gray, photos showing firearms and ammunition unsecured in a bedroom closet, and testimony from the teen’s mother, grandmother and sister about Colt’s deteriorating mental health.

The defendant’s estranged wife, Marcy Gray, who struggled with drug and alcohol addiction, testified that her son was anxious, easily agitated, and had panic attacks. She said it was “very obvious” that he needed professional help, but her husband “just didn’t want to deal with it.”

Notably, the jury viewed body camera footage from May 21, 2023, when Jackson County Sheriff’s Office deputies visited Colt and Collin Gray’s home after receiving an FBI tip about online threats to attack the school. Colt denied posting the threat, but law enforcement was ultimately unable to corroborate the information. Colin Gray bought his son an AR-15 style rifle later that year.

The defense called only one witness, Colin Gray himself. He testified that he bought firearms and ammunition to get his son interested in the outdoors and foster a bond between father and son. She also said she plans to provide counseling for Colt at school regarding his mental health issues and that she does not feel her son is a threat.

“He’s a good kid,” his father said through tears. “He wasn’t perfect, and I wasn’t perfect, but to do something so heinous, no one would ever see something so evil. The Colt I knew, the relationship I had, there was a whole other side of Colt I didn’t know.”

But under tense cross-examination, he acknowledged that several firearms were kept unsecured and unlocked in a closet, and said Colt sometimes kept an AR-15-style rifle in his bedroom. He struggled to explain that Colt did not attend school throughout his entire eighth-grade year, according to school records.

She admitted that she was aware that her son had been physically violent, that she had a photo of the school shooter on her bedroom wall, and that she had sent him a text message weeks before the attack saying, “If something happens, just know I have blood on my hands.”

Finally, the jury saw harrowing surveillance video of Colt Gray’s movements on the morning of the September 4, 2024, school shooting. School officials and resource personnel picked up Colt Gray that morning after he made some concerning statements, but in a stranger-than-fiction mix-up, they confused him with another student named Colton Gray.

Colt Gray then armed himself with a rifle he had brought to school hidden in his backpack and opened fire indiscriminately into the math class, killing several people in the hallway. Teachers Richard Aspinwall and Christina Irimy and students Mason Schermerhorn and Christian Angulo were killed.

This story has been updated with additional information.