The Georgia Bureau of Investigation also arrested the teen's father, Colin Gray, on Sept. 5, and prosecutors have charged him with two counts of murder, four counts of involuntary manslaughter and eight counts of child cruelty.

The teen suspect was questioned last year about online threats, though nothing conclusive emerged. Many local police departments lack the resources to take deeper looks at suspicious actors.

On the morning of the shooting at a Winder, Georgia high school that left four people dead, authorities were “actively looking” for the teenage suspect after the school received a warning call from his mom – but they weren’t able to get to him fast enough because of an identification issue,