Audrey Hale, 28, was under a doctor's care for an unspecified emotional disorder at the time of the attack, the Nashville police chief, John Drake, said yesterday.
Drake said he believed those killed at the Covenant school, including three nine-year-olds, were not specifically targeted.
"We've determined that [the killer] bought seven firearms from five different gun stores here legally," Drake said. "Three of those weapons were used yesterday during the horrific tragedy.
"Law enforcement knew nothing about the treatment she was receiving but her parents felt she should not own weapons. They were under the impression that she sold one weapon and did not own any more. As it turned out, she had been hiding several weapons within the house."
Police released highly dramatic body-camera video of officers moving though the school and confronting and killing the attacker. The officers, Drake said, "heard gunfire, immediately ran to that, and took care of this horrible situation".
The video prompted many to draw a contrast between the handling of the Nashville shooting and the one last year at an elementary school in Uvalde, Texas, where officers waited more than an hour to confront and kill an intruder who killed 19 children and two teachers.
However, Nashville law enforcement has been accused of failing to respond properly to a report that Hale sent social media messages to a friend before the attack, warning: "Something bad is about to happen."
Drake did not address the matter at yesterday's briefing.
The messages to a former middle school basketball teammate, sent less than an hour before the killings, were "basically a suicide note", the attacker wrote, and "you'll probably hear about me on the news after I die".
This story is from the March 29, 2023 edition of The Guardian.
Start your 7-day Magzter GOLD free trial to access thousands of curated premium stories, and 9,000+ magazines and newspapers.
Already a subscriber ? Sign In
This story is from the March 29, 2023 edition of The Guardian.
Start your 7-day Magzter GOLD free trial to access thousands of curated premium stories, and 9,000+ magazines and newspapers.
Already a subscriber? Sign In
Postecoglou claims coach's life is harder than being PM
A Premier League manager has a tougher job than the prime minister, according to Ange Postecoglou.
Rashford rebuked Players must talk to manager not media - Amorim
Ruben Amorim has said when he was a player he would have spoken to his manager about being dropped rather than react in the media, as Marcus Rashford has done.
Tonali double puts rampant Newcastle into last four
A sticking plaster for Newcastle's internal tensions or a potential long-term cure for their problems? Whatever the reality Eddie Howe's inconsistent team are a two-leg semi-final away from a potentially transformative Wembley showpiece after two stellar first-half goals from Sandro Tonali and another from Fabian Schär undid an immensely disappointing Brentford on Tyneside.
Jesus hat-trick delivers early Christmas gift as Arsenal topple Palace
It seems fitting that Gabriel Jesus should have chosen this time of year to end his goalscoring drought.
Elliott the difference as Rusk's Southampton put up late fight
It was a night that Simon Rusk will never forget, the one when he took charge of Southampton for the first time in the wake of Russell Martin's sacking and carried the fight to Arne Slot and Liverpool.
United circus has derailed Rashford but fresh start is no guarantee of success
It was two years ago yesterday that Argentina won the World Cup. England had gone out to France in the quarterfinals and, beyond the usual kneejerk attacks on Gareth Southgate, there was a sense of general optimism.
Maresca still 'trusts' Mudryk after failed drugs test
Enzo Maresca has thrown his support behind Mykhailo Mudryk, saying he believes the Chelsea winger's insistence that he is innocent of taking a banned substance.
Caldentey's late spot-kick secures first place for Arsenal
A late Mariona Caldentey penalty powered Arsenal to the top of Group C in the Champions League at Bayern Munich's expense after a Magda Eriksson double looked to have secured a draw for the visitors.
Taylor 'desperate' for a break as brilliant Barça take top spot from City
Manchester City's head coach, Gareth Taylor, says his team desperately need the upcoming winter break to bolster their squad, after they were comprehensively outplayed by a Barcelona side who reminded everybody why they are the reigning European champions with an emphatic win.
Freddie calls up Flintoff as teen makes the grade for Lions tour
Rocky Flintoff has been called up to his father's Lions squad for next month's tour of Australia, with England using the trip to give young bowlers who are already in contention for a place in the senior Test squad experience of local conditions before next winter's Ashes.