The 14-year-old boy accused of fatally shooting four people at a Georgia high school was expected to make his first court appearance on Friday, a day after his father was also arrested for allegedly allowing his son to possess a weapon.

Colt Gray, who is charged as an adult with four counts of murder, will appear by video from a youth detention facility for the proceedings at the Barrow County courthouse. The hearing will be held two days after authorities said the teenager opened fire at Apalachee High School in Winder, just outside Atlanta.

The boy’s father, Colin Gray, 54, was charged on Thursday with four counts of involuntary manslaughter, two counts of second-degree murder and eight counts of cruelty to children, Georgia Bureau of Investigation director Chris Hosey said.

“His charges are directly connected with the actions of his son and allowing him to possess a weapon,” Mr Hosey said. Colin Gray’s first court appearance has not been set.

Father and son have been charged in the deaths of students Mason Schermerhorn and Christian Angulo, both 14, and teachers Richard Aspinwall, 39, and Cristina Irimie, 53, according to Mr Hosey. Nine other people were injured, seven of them shot.

It is the latest example of prosecutors holding parents responsible for their children’s actions in school shootings.

In April, Michigan parents Jennifer and James Crumbley were the first convicted in a US 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.

Arrest warrants obtained by the Associated Press accuse Colt Gray of using a semiautomatic assault-style rifle in the attack. Authorities have not offered any motive or explained how he obtained the gun and got it into the school.

The teenager denied threatening to carry out a school shooting when authorities interviewed him last year about a menacing post on social media, according to a sheriff’s report obtained on Thursday.

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.

The attack was the latest among dozens of school shootings across the US in recent years, including especially deadly ones in Newtown, Connecticut; Parkland, Florida; and Uvalde, Texas. The classroom killings have set off fervent debates about gun control but there has been little change to national gun laws.

It was the 30th mass killing in the US so far this year, according to a database maintained by the AP and USA Today in partnership with Northeastern University. At least 127 people have died in those killings, which are defined as events in which four or more people die within a 24-hour period, not including the killer — the same definition used by the FBI.