Georgia state officials arrested the father of the 14-year-old suspected in a school shooting that killed four people and wounded nine others on Wednesday, saying the father knowingly allowed his son to have the murder weapon.

Colin Gray, 54, was charged with four counts of involuntary manslaughter, two counts of second-degree murder and eight counts of cruelty to children, the Georgia Bureau of Investigation said.

"These charges stem from Mr. Gray knowingly allowing his son Colt to possess a weapon," Chris Hosey, director of the Georgia Bureau of Investigation, told a press conference.

Colt Gray, 14, has been charged with four counts of felony murder and would be tried as an adult, officials said. His arraignment is set for Friday morning before a Georgia Superior Court judge in Barrow County by video camera.

Georgia state and Barrow County investigators say the younger Gray used an "AR platform style weapon," or semiautomatic rifle, to carry out the attack in which two teachers and two 14-year-old students were killed.
It remained unclear exactly how the son came into possession of the weapon.

Investigators have yet to comment on what may have motivated the first U.S. campus mass shooting since the start of the school year.

The shooting at Apalachee High School in Winder, a city of 18,000 some 50 miles (80 km) northeast of Atlanta, revived both the national debate about gun control and the outpouring of grief that follows in a country where such attacks occur with some regularity.

Officials identified those killed as two 14-year-old students, Mason Schermerhorn and Christian Angulo, and two teachers, Richard Aspinwall, 39, and Cristina Irimie, 53.

Two teachers and seven students were wounded in the attack, some of whom have been released from the hospital, Barrow County Sheriff Jud Smith told reporters.

"The nine injured, I am very happy to say, will make a full recovery," Smith told reporters.

The charging of the father could represent a new strategy in America's halting attempt to control the epidemic of school shootings.