The 28-year-old, who is believed to be a former student at Covenant Presbyterian Church School, was shot dead by police on an upper floor of the school.
Hale had shot open a side door before opening fire on students and staff with two assault-style rifles and a handgun.
Metro Nashville Police Chief John Drake said Hale was not believed to have any previous criminal record.
He said a “manifesto” and a map of the school grounds showing entrances had been found at the killer’s home.
Asked at a press conference whether there was anything found in a police search of Hale’s apartment that could have suggested a motive for such a horrific crime, Chief Drake said: “We have a manifesto, we have some writings we’re going over that pertain to this day, the actual incident.
“We have a map drawn out of how this was all going to take place.
“There’s right now a theory that we may be able to talk about later but it’s not confirmed, and so we’ll put that out as soon as we can.”
Police have identified the suspected shooter by their name at birth; Hale reportedly was a transgender man who used he/him pronouns, though law enforcement officials initially described the suspect as a woman in the aftermath of the shooting. Police did not provide another name.
In answer to a question as to whether Hale’s transgender status might have any bearing on a motive, Chief Drake said: “There is some theory to that. We’re investigating all the leads and once we know exactly, we will let you know.”
He said that the attack was targeted.
Chief Drake added that while there was no known history of mental illness, it was a lead that was being investigated.
He also said Hale had been considering targeting another location – which was not identified – but had apparently decided not to because of the level of security around it.
“Right now we believe it was a lone assailant, and we don’t anticipate any further damage at this time.”
A LinkedIn account suggests Hale was an illustrator and graphic designer based in Nashville. The account says Hale was working for AH Illustrations and had previously been an illustrator at Nossi College of Art. It also mentions jobs with Grocery Shopper and as a cat sitter.
A neighbour, Sandy Durham, told the Daily Beast: “I do know Audrey, I’ve known her since she was a baby. I had just gotten out of the shower when all of this started happening. I didn’t really know anything more than that. Something was going on next door. It’s just tragic for everybody. The sweet children that were hurt, killed, the adults. All of it.”
Asked if there were any warning signs she said: “Never. She was very sweet. I don’t know what happened. It’s very scary.”
The killer’s name was released as the six victims were also identified.
Evelyn Dieckhaus, Hallie Scruggs and William Kinney, all aged 9, were fatally shot.
Katherine Koonce, age 60, and Cynthia Peak and Mike Hill, both age 61, were also among the six victims.
Koonce is listed on The Covenant School’s website as “head of school.”
Hill was a school custodian, and Peak was a substitute teacher, according to law enforcement officials speaking to reporters on 27 March.
Alex Woodward contributed reporting