WINDER, Ga. (AP) — The father of a teenager accused of a deadly high school shooting in Georgia was aware that his son was obsessed with school shooters and even had a shrine above his home computer for the gunman in the 2018 massacre in Parkland, Florida, prosecutors said at a Wednesday court hearing.

Colin Gray had also given his son, Colt, the assault-style weapon used in the shooting that killed four people at Apalachee High School as a Christmas gift and was aware that his son’s mental health had deteriorated in the weeks before the shooting, investigators testified.

Colt Gray, 14, charged with four counts of murder, is accused of using the gun to kill two fellow students and two teachers on Sept. 4 at the high school in Winder, outside Atlanta. Because he’s a juvenile, the maximum penalty he would face is life without parole.

Georgia Bureau of Investigation Agent Kelsey Ward said in court Wednesday that Colin Gray, 54, had asked his son who the people in pictures hanging on his wall were. One of them, Colt told his father, was Nikolas Cruz, the shooter in the 2018 massacre at Marjory Stoneman Douglas High School in Parkland, Florida.

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Investigators say they also found a notebook Colt had left behind at the school, with one page that included the labels “hallway” and “classroom” at the top.

In the hallway column, it says “I’m thinking 3 to 4 people killed. Injured? 4 to 5,” GBI agent Lucas Beyer testified. “Under the classroom column is written 15 to 17 people killed, Injured? 2 to 3.”

Ward interviewed several family members, including Colt’s mother, Marcee Gray.

“She said that over the past year his fascination with guns had gotten very bad,” Ward testified.

At one point, Colt asked his dad to buy him an all-black “shooter mask,” saying in a joking manner that, “I’ve got to finish up my school shooter outfit, just kidding,” Ward said.

Colt’s parents had discussed their son’s fascination with school shooters, but decided that it was in a joking context and not a serious issue, Ward said.

For Christmas before the shooting, Colin Gray purchased the weapon for his son, Barrow County sheriff’s investigator Jason Smith testified. Later, Colt asked his father for a larger magazine for the gun so it could hold more rounds and his father agreed, Smith said. Colin Gray also purchased the ammunition, Smith said.

Colin Gray has been charged with involuntary manslaughter and second-degree murder related to the shooting. Arrest warrants said he caused the deaths of others “by providing a firearm to Colt Gray with knowledge that he was threat to himself and others.”

Gray’s lawyers, Jimmy Berry and Brian Hobbs, did not immediately respond to requests for comment Wednesday from The Associated Press. In court on Wednesday, they mainly asked questions of the witnesses and did not make statements regarding their client’s actions.

The judge on Wednesday decided that prosecutors met the standard to continue their case against the father, and the case will now move to Superior Court.

The charges came five months after Michigan parents Jennifer and James Crumbley were the first convicted in a U.S. mass school shooting. They were sentenced to at least 10 years in prison for not securing a firearm at home and acting indifferently to signs of their son’s deteriorating mental health before he killed four students in 2021. The Georgia shooting has also renewed debate about safe storage laws for guns and prompted other parents to figure out how to talk to their children about school shootings and trauma.

Colt Gray denied threatening to carry out a school shooting when authorities interviewed him last year about a menacing post on social media, an earlier sheriff’s report said. Conflicting evidence on the post’s origin left investigators unable to arrest anyone, the report said. Jackson County Sheriff Janis Mangum said she reviewed the report from May 2023 and found nothing that would have justified bringing charges at the time.