Colin Gray, left, and his son Colt, were indicted on charges related to the mass shooting at Apalachee High School in Winder, Georgia, last month.
CNN  — 

A Georgia grand jury indicted a father and son on murder and other charges Thursday in the mass shooting at Apalachee High School in Winder, Georgia, last month that left four people dead and another nine injured.

Colt Gray, 14, was indicted on a total of 55 counts, including four counts of felony and malice murder, plus aggravated assault and cruelty to children.

His father, Colin Gray, was indicted on 29 counts, including two counts of second-degree murder, two counts of involuntary manslaughter, and multiple counts of second-degree cruelty to children and reckless conduct.

Thursday’s indictment adds additional charges to the case. Last month, Colt Gray was arraigned on four counts of felony murder, and Colin Gray was arraigned on four counts of involuntary manslaughter, two counts of second-degree murder and eight counts of cruelty to children.

The indictment charges Colt Gray with felony and malice murder and states that he committed the crimes with forethought. The document accuses Colin Gray of “criminal negligence” and cruelty to children in the second degree by allowing his son, a minor under his custodial responsibility, “access to a firearm and ammunition after receiving sufficient warning that Colt Gray would harm and endanger the bodily safety of another.”

Colt Gray is accused of fatally shooting two 14-year-old students – Mason Schermerhorn and Christian Angulo – and two math teachers – Richard Aspinwall and Cristina Irimie – on September 4. Eight students and one teacher were wounded.

The teen will be tried as an adult. And the charges against his father push the boundaries of who is responsible for a mass shooting.

The case marks just the second time in America a parent has been charged in connection with a mass shooting by a minor, after Jennifer and James Crumbley, the parents of Michigan school shooter Ethan Crumbley, were found guilty of involuntary manslaughter and sentenced to 10 to 15 years in prison.

Investigators testified Wednesday that Colin Gray knew of his son’s deteriorating mental state and his fascination with campus shootings ahead of the rampage.

At a preliminary hearing, chilling details were revealed about what was found in the Gray home on the day of the shooting, including a notebook containing drawings by Colt Gray depicting stick figures with wounds. “Shoot the teacher first” was written next to the images. A note found in the home’s gaming room read, “Forgive me. It is out of my control. See you.”

Investigators said clues in the home pointing to potential violence were overlooked or not sufficiently addressed. Colt had made a shrine to school shootings, which included at least one photo of the Parkland, Florida, shooter, according to Georgia Bureau of Investigation special agent Kelsey Ward.

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Mother of suspected Georgia shooter explains what led her to warn school about son
00:54 - Source: CNN

Investigators testified Colin Gray was in touch with school staff in the weeks before the shooting about his son’s need for counseling and sent in a form, but failed to follow up and ensure his son made appointments. A school counselor said Colin Gray indicated he may not be able to afford the care.

Colt Gray also sent concerning text messages to his parents minutes before the shooting. And while his mother Marcee Gray called Apalachee pleading for staff to find her son, Colin Gray did not call. When deputies showed up at his home, Colin Gray did not appear remorseful, Ward testified.

In May 2023, law enforcement questioned Colt and his father about online threats “to commit a school shooting,” the FBI has said. Colt at the time denied making the threats, and his father told authorities his son did not have unsupervised access to hunting guns in the house. Just seven months later, the suspect’s father purchased the firearm allegedly used in the mass shooting as a holiday present for his son, two law enforcement sources told CNN.

On the day of the shooting, the 14-year-old was allowed to leave the classroom with his belongings before returning with a rifle in his backpack, the state Bureau of Investigation said at the time of the incident. He had brought the gun with him on the school bus with “something wrapped around it as if it was a school project,” Barrow County Sheriff Jud Smith told CNN affiliate WXIA. The school did not have metal detectors, according to authorities.

CNN’s Cindy Von Quednow, Phil Gast, Rebekah Reiss, Holy Yan, Emma Tucker and Dalia Faheid contributed to this report.