The shooter who killed three children and three adults at The Covenant School in Nashville used three of seven legally purchased firearms in America's latest massacre.
Audrey Hale, a 28-year-old former student who was under care for an emotional disorder, was in possession of an AR-15 military-style rifle, a 9 mm Kel-Tec SUB2000 pistol calibre carbine, and a 9 mm Smith and Wesson M&P Shield EZ 2.0 handgun, according to Metro Nashville Police Chief John Drake.
The AR-15 and 9 mm pistol calibre carbine appear to have 30-round magazines, according to experts who reviewed photos and video released by police.
"It indicates that they were prepared to wreak a lot more havoc than they were able to actually carry out thanks to the relatively quick action from the police," said CNN analyst Stephen Gutowski, founder and editor of The Reload, a firearms website.
The attack at the private Christian school lasted about 14 minutes before the shooter was shot and killed by police.
It's still unclear what motivated the slaughter.
Here's what we know about the guns used in Monday's assault -- the deadliest US school shooting since last May's massacre in Uvalde, Texas, left 21 people dead.
Weapons purchased between 2020 and 2022
Hale had legally bought seven firearms and had kept them hidden at home, according to Drake
The seven firearms were purchased between October 20, 2020, and June 6, 2022, police spokesman Don Aaron said.
A search warrant executed at the home led to the seizure of a sawed-off shotgun, a second shotgun and other evidence, according to police.
The shooter's parents told police they knew Hale had bought and sold one weapon and believed that was the extent of it.
Police know Hale left home Monday morning with a red bag and that Hale's mother did not know weapons were inside, Drake said.
Three of the guns Hale owned were used to kill three 9-year-olds as well as a custodian, a substitute teacher and the head of the school.
After meeting with the shooter's parents and school officials, authorities have yet to uncover any specific issues or problems in the attacker's past, according to Drake.
The parents felt Hale "should not own the weapons," the chief said.
Tennessee does not have a "red flag" law that would allow a judge to temporarily seize guns from someone believed to be a threat to themselves or others.
Drake said police did not know about Hale's issues. No evidence has surfaced that Hale was believed to be a threat before this week.
"Law enforcement was never contacted," Drake said. "She was never committed to an institution."
The shooter is believed to have had weapons training, Aaron told CNN. The department is working to determine when and where that training would have taken place, he added.
3 guns used in massacre are common in US
Carrying the three firearms, the shooter entered the school by firing at glass doors and climbing through. Hale walked down the hallways and pointed an assault-style weapon, according to surveillance video released by Metro Nashville Police.
The first call to police was at 10:13 a.m. Officers arrived at 10:24 a.m. Three minutes later, police said, the shooter was dead.
The three guns Hale used at the school are common, with the AR-15 the most common rifle in the country, according to Gutowski. The assault-style rifle holds a unique place in the heated political debate over gun control, he said -- a symbol of the Second Amendment bulwark.
CNN analyst Jennifer Mascia, writer and a founding staffer of The Trace, a non-profit focused on gun violence, said there have been at least six other mass shootings with assault-style rifles in K-12 schools over the last decade, dating to the Sandy Hook massacre in 2012.
Handguns are used more often in mass shootings, but semi-automatic rifles rarely leave survivors.
"That's because when a rifle round makes contact, it will twist and turn sideways, carving a wide path through human tissue," she said.
The pistol calibre carbine has a 16-inch barrel but shoots the same ammunition as the 9 mm handgun, according to Gutowski.
In a scenario where an armed assailant attacks defenceless victims, Gutowski said, the kind of firearm they use "is, unfortunately, only likely to marginally change the outcome."
Tennessee's lax gun laws set a low bar
Tennessee has some of the weakest gun laws in the nation.
Most mass shooters get their guns legally and, in Tennessee, the bar for acquiring a firearm is extraordinarily low, according to Mascia.
"It's perfectly legal in Tennessee to buy a gun without a background check," she said. "Tennessee in 2021 became the 25th permitless carry state. So you could carry a gun in public without ever having a background check."
And Tennessee is one of about 30 US states with no red flag laws, which allow police and courts to take away guns from potentially dangerous people, according to CNN analyst Abené Clayton, lead reporter on The Guardian's "Guns & Lies in America" series.
"There's no infrastructure for concerned people," Clayton said. "Clearly, this individual's parents were concerned and, by all accounts, having a system that they could use to alert local authorities or to get a petition from a judge to have guns removed is certainly something I think a lot of folks wish would have been available."
In the end, the actions of teachers who locked down classrooms that day prevented further bloodshed, said security consultant Brink Fidler, a former police officer who provided active shooter training at the school.
The shooter fired multiple rounds into several classrooms but didn't hit any students "because the teachers knew exactly what to do, how to fortify their doors and where to place their children in those rooms," Fidler said.
Correction: A previous version of this story incorrectly reported Jennifer Mascia's role at The Trace. She is a founding staffer.
