Four were killed in the shooting at Apalachee High School in Winder, Georgia.
Meanwhile, as investigators worked to determine a motive behind Wednesday's deadly school shooting in Georgia, they said they were also seeking answers about the weapon allegedly used by the 14-year-old suspect.
The shooting early Wednesday at Apalachee High School in Winder killed two students and two teachers, according to the Georgia Bureau of Investigation.
Also slain were teachers Richard Aspinwall, 39, and Christina Irimie, 53, and students Mason Schermerhorn, 14, and Christian Angulo, 14, officials said. Nine others were injured, officials said.
The suspect, Colt Gray, was a student at the school. In a Wednesday self-surrender, he is currently in police custody, says the GBI. He will be charged with murder and is going to face trial as an adult, the GBI says.
He was being held Thursday morning at Gainesville Regional Youth Detention Center, according to the Department of Juvenile Justice, which told ABC News' affiliate WSB.
People leave Apalachee High School, Wednesday, Sept. 4, 2024, in Winder, Ga.
Chris Hosey, director of the GBI, said Wednesday night an AR-platform-style weapon was used in the incident.
Officials said they did not yet have any answers for how Gray was allegedly able to obtain the gun to get it into the school. County Sheriff Jud Smith said Gray was interviewed by investigators and GBI, but did not disclose further details.
A motive has not been determined and it is not clear if the victims were targeted, police said.
People hold candles while attending a vigil at Jug Tavern Park following a shooting at Apalachee High School in Winder, Georgia, on Sept. 4, 2024.
The FBI said Wednesday that the Jackson County Sheriff's Office, acting on a caution, spoke with the alleged shooting suspect in 2023.
"In May 2023, the FBI's National Threat Operations Center received multiple anonymous tips about online threats to commit a school shooting at an unidentified location and time," an FBI post read.
The FBI added, "Within 24 hours, the FBI determined the online post originated in Georgia and the FBI's Atlanta Field Office referred the information to the Jackson County Sheriff's Office for action."
ABC News' Alexandra Faul, Josh Margolin, Brandon Baur, Faith Abubey, Miles Cohen, Emily Shapiro, Meredith Deliso and Jessica Gorman contributed to this report.