Winder, Georgia - A man whose teenage son shot dead four people at a Georgia high school was found guilty of murder and manslaughter on Tuesday in a rare case of a parent charged over a shooting carried out by their child.

Colin Gray (55) was convicted by a jury of second-degree murder, involuntary manslaughter, and other offenses in connection with the September 2024 shooting at Apalachee High School by his troubled son, Colt.

Two 14-year-old students and two teachers were killed, and nine people were wounded in the shooting in Winder, Georgia. Colt Gray, who was 14 then and is now 16, has been charged as an adult and is awaiting a trial date.

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During opening arguments of the two-week trial of the father, prosecutors said he bought Colt Gray the AR-15-style rifle used in the shooting for Christmas 2023 despite warnings that his son had threatened to carry out a school shooting.

According to the FBI, sheriffs interviewed the then-13-year-old Gray and his father in May 2023 after receiving anonymous tips about online threats to commit a school shooting.

"This case is about this defendant and his actions, allowing a child that he has custody over access to a firearm and ammunition after being warned that that child was going to harm others," Barrow County district attorney Brad Smith said.

Defense attorney Brian Hobbs told the jury that Colin Gray was unaware of his son's intentions and had sought help for his deteriorating mental health.

School shootings are a shockingly regular occurrence in the US, where guns outnumber people and regulations on purchasing even powerful military-style rifles are lax.

Parental responsibility in mass shootings has come increasingly under the spotlight in recent years.

The parents of a teenager who shot and killed four people at a Michigan high school in 2021 were convicted of manslaughter charges in 2024 and sentenced to 10 to 15 years in prison in an unprecedented and closely watched case.

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Jennifer and James Crumbley were the first parents of a school shooter convicted of involuntary manslaughter in the US for the actions of their child.

Colin Gray is believed to be the first parent to be charged with murder over a shooting carried out by their child.

Polls show a majority of US voters favor stricter controls on the purchase of firearms, but the powerful National Rifle Association gun lobby is opposed to additional restrictions and lawmakers have repeatedly failed to act.