The father of the 14-year-old boy accused of carrying out a deadly mass shooting at Georgia's Apalachee High School appeared in court on Thursday morning for a pre-trial motions hearing.

Colin Gray and his son, Colt Gray, were both indicted in the Sept. 4 shooting that killed two students and two teachers and injured nine others. The Winder man is the first adult known to be charged in a school shooting in Georgia.

During Thursday's hearing, Gray's defense said that they planned to argue that search warrants in the case did not apply to specific cellphones and statements their client told police were not given with valid consent.

The attorneys also questioned an investigator about discussions they had with Colin Gray while looking into possibly threatening posts on social media in 2023. No charges were filed in that investigation. A second investigator discussed one of the statements that Colin Gray made to her in the hours after the shooting.

Colt Gray is charged as an adult and was indicted on 55 counts, including murder and 25 counts of aggravated assault at the high school. His father was indicted on 29 counts, including two counts of second-degree murder and two counts of involuntary manslaughter. Both also face multiple counts of cruelty to children.

Both father and son have pleaded not guilty to the charges they face.

At a hearing in 2024, investigators testified that Colin Gray was aware that his son's mental health had deteriorated in the weeks before the shooting, but still gave the teen the assault-style weapon as a Christmas gift and purchased a laser sight, tactical vest, and ammunition for him. Gray was also aware that his son was obsessed with school shooters and even had a shrine above his home computer for the gunman in the 2018 Parkland, Florida, school massacre, prosecutors said.

Colin Gray's trial was originally set to begin in September, but the start was postponed due to scheduling conflicts until February 2026. Colt Gray's trial date has not been scheduled as he waits for a medical evaluation.

Earlier this year, a judge agreed that jurors in the elder Gray's trial would be selected from outside Barrow County out of concern that the case's publicity may have tainted the opinions of locals. 

The Associated Press contributed to this report.