More than a year ago, tips about online posts threatening a school shooting led Georgia police to interview a 13-year-old boy, but investigators didn’t have enough evidence for an arrest. On Wednesday, that boy opened fire at his high school outside Atlanta and killed four people and wounded nine, officials said.

The teen had been interviewed after the FBI received anonymous tips in May 2023 about online threats to commit an unspecified school shooting, the agency said in a statement.

The FBI narrowed the threats down and referred to the case to the sheriff’s department in Jackson County, which is adjacent to Barrow County.

The sheriff’s office interviewed the then-13-year-old and his father, who said there were hunting guns in the house but the teen did not have unsupervised access to them. The teen also denied making any online threats. The sheriff’s office alerted local schools for continued monitoring of the teen, but there was no probable cause for arrest or additional action, the FBI said.

The teen has been charged as an adult in the deaths of Apalachee High School students Mason Schermerhorn and Christian Angulo, both 14, and instructors Richard Aspinwall, 39, and Christina Irimie, 53, Georgia Bureau of Investigation director Chris Hosey said.

At least nine others were taken to hospitals with injuries. All were expected to survive, Sheriff Jud Smith said.