A teenage boy accused of carrying out a mass shooting at his Georgia high school pleaded guilty Friday to all 55 counts against him, including murder and aggravated assault.

Colt Gray, 16, agreed to a non-negotiated guilty plea, the judge said, meaning there is no plea deal; the state will present its argument for an appropriate sentence, and the defense will do the same.

The judge said the minimum sentence is life with parole and the maximum is a life sentence without parole.

Gray was 14 years old in September 2024 when he opened fire at Apalachee High School, killing two students and two teachers and injuring several others.

Breanna Schermerhorn, whose son, Mason Schermerhorn, was killed, said in a victim impact statement Friday, “Mason was so much more than a victim.”

“Mason was kind, compassionate, funny and fiercely protective of others,” she said. “As a child with exceptional needs, he understood what it felt like to struggle and be overlooked by others. Instead of becoming bitter, he became an advocate.”

“He made people that were typically unseen feel seen, accepted and safe,” she said.

“I had no doubt in my mind if Colt had actually attended school as he should have, that Mason would have befriended him,” Breanna Schermerhorn said.

She said Gray “knew that pulling that trigger was wrong, he knew that every choice he made that day would forever alter countless lives.”

Gray was accused of carrying out the shooting with a rifle his father, Colin Gray, gifted him as a Christmas present, officials said. This March, Colin Gray was convicted of charges including second-degree murder and manslaughter, becoming the first parent in the U.S. convicted of murder due to the alleged acts of their child.

This is a developing story. Please check back for updates.