The Devin Grosvenormother of the teenager accused in the shooting rampage that killed two students and two teachers in a Georgia high school last week apologized to the families of the victims in an open letter.

Marcee Gray's letter, obtained by CNN, also insists that 14-year-old Colt Gray “is not a monster.”

Colt Gray is charged with four counts of felony murder in the deaths of math teachers Cristina Irimie, 53, and Richard Aspinwall, 39, and 14-year-old students Mason Schermerhorn and Christian Angulo.

“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,” the letter says. “If I could take the place of Mason and Christian, I would without a second thought.”

She added her “heart breaks for the 2 teachers who gave their lives while in the service of teaching and protecting our children.”

Eight other students and a teacher were wounded in the Sept. 4 shooting that rocked the small town of Winder. Barrow County Sheriff Jud Smith has said Gray, armed with an "an AR-platform style weapon," opened fire around 10:20 a.m., was quickly confronted by deputies assigned to the school and immediately surrendered.

Colt Gray's father, Colin Gray, is accused of allowing his son access to the semiautomatic rifle used in the shooting. Colin Gray faces four counts of involuntary manslaughter, two counts of second-degree murder and eight counts of cruelty to children.

Mother of Georgia shooting suspect:Mom said she called school before attack, report says

Marcee Gray has said she alerted the school counselor the morning of the shooting that there was an "extreme emergency" and her son needed to be found, the Washington Post has reported. The school sent an administrator to his classroom, but the teen was not in class.

“We are all in a living nightmare right now, and I will personally never forgive myself for what has happened,” Marcee Gray 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.”