The 14-year-old charged with shooting up a Georgia high school last week brought a rifle into the school inside his backpack, authorities said.
Colt Gray brought the gun to Apalachee High School in Winder on his own on Sept. 4, the Georgia Bureau of Investigation (GBI) confirmed.
The assault-style rifle could not be broken down, but Gray hid it in his backpack, authorities added.
"It would have stuck out, but he had some things that made it concealed," Barrow County Sheriff Jud Smith told WSB-TV Atlanta.