STORY: Nashville police released a school video showing the assailant, identified by police as Audrey Elizabeth Hale, blasting through glass doors with gunfire and roaming the halls, pointing a semi-automatic rifle.

The suspect wore a black vest over a white T-shirt, camouflage pants and a backwards red baseball cap in a video that showed only the shooter in the frame.

The motive was not immediately known, but Hale had drawn detailed maps of the school, including entry points for the building, and left behind a "manifesto" and other writings that investigators were examining, Police Chief John Drake told reporters.