A Georgia grand jury Thursday charged a father and son for a school shooting that killed two students and two teachers.

The grand jury, a group of civilians tasked by the court with determining whether the evidence supports a criminal charge, found probable cause against both the father, Colin Gray, and the son and shooter, Colt Gray. They indicted the son on 55 counts, including murder, and the father on 29 counts, including second-degree murder, involuntary manslaughter, and cruelty to children. The hearing where they will formally respond to these criminal charges is scheduled for November 21.

Charges against the elder Gray are based on him giving his son access to guns and ammunition “after receiving sufficient warning that [his son] would harm and endanger the bodily safety of another.” The “sufficient warning” refers to the son’s history of mental instability coupled with a known obsession with guns and school shooters. Georgia law enforcement have stated that the father bought his son the semi-automatic rifle that was used in the shooting, as well as “a tactical vest, ammunition and sight for the weapon and larger-capacity magazines for the rifle at his son’s request.”

This is the second case in the US where a parent has been criminally charged in relation to their child’s school shooting. Earlier this year, a Michigan judge sentenced the parents of a school shooter 10 to 15 years in prison for involuntary manslaughter arising from their criminal negligence.