Colt Gray, the 14-year-old suspected Apalachee High School gunman who allegedly killed four people, purportedly hid the AR-15 he used to carry out last week's deadly attack in his backpack to get it onto school grounds.
According to the Georgia Bureau of Investigation, the semi-automatic rifle could not be broken down, but Gray managed to hide it in his backpack and bring it onto the Winder, Georgia, campus Sept. 4.
Moments before the shooting, the teen allegedly asked his classroom teacher if he could go speak to someone in the front office. The teacher gave him permission to leave with his belongings. Gray then allegedly went to the restroom to hide. He later took out the AR-15 and started shooting, the GBI alleged Thursday.
Gray is accused of killing students Christian Angulo and Mason Schermerhorn, both 14; and math teachers, Cristina Irimie, 53, and Richard Aspinwall, 39.
Nine others were shot.
It's unclear if the victims were targeted and a motive remains under investigation.
Gray has since been charged with four counts of murder and will be tried as an adult.
His father, Colin Gray, 54, has also been charged with four counts of involuntary manslaughter, two counts of second-degree murder, and eight counts of cruelty to children.
On Wednesday, Gray's mother, Marcee Gray, penned an open letter apologizing for her son's alleged actions.
"To the parents and families of those affected by the tragic events at Apalachee High School, I want to say that I am so sorry from the bottom of my heart," she wrote, according to CNN.
"If I could take the place of Mason and Christian, I would without a second thought," the letter read. "As a parent, I've always said that the loss of one of my children would be the only thing that I wouldn't be able to come back from. I feel all of your pain and devastation. I grieve and cry with you."
"We are all in a living nightmare right now, and I will personally never forgive myself for what has happened," she wrote. "My son Colt is not a monster. He is my oldest baby. He is quiet, thoughtful, caring, funny, and extremely intelligent. Please pray for him and the rest of our family, as I am praying for all of you every moment of every day."
