Yahoo TV

STORY: Bodycam footage released on Tuesday showed Nashville, Tennessee, police officers racing through the halls of a private Christian grade school where an attacker killed three 9-year-old students and three adult staff members moments before they confronted and fatally shot the suspect.

"Stop moving! Stop moving!"

Police have identified the shooter as Audrey Elizabeth Hale, a 28-year-old former student at the Covenant School who self-identified as transgender.

At a news conference, Metro Nashville Police Chief John Drake said Hale had an "emotional disorder" and had purchased the weapons used in Monday's attack legally.

"We've interviewed the parents of Audrey Hale, and we've determined that Audrey bought seven firearms from five different local gun stores here, legally. They were legally purchased. Three of those weapons were used yesterday during this horrific tragedy that happened... She was under care, doctor's care, for an emotional disorder. Law enforcement knew nothing about the treatment she was receiving... We also don't have a motive at this time. We feel that these students that were targeted were randomly targeted. There was not any particular student that they were, that she was looking for at the time of the incident."

Investigators are examining what they called a "manifesto" that Hale left behind, hoping to learn what motivated the latest in a long string of U.S. mass shootings.

Police said the manifesto indicated that Hale - who also had a detailed, hand-drawn map of the school - planned to carry out additional shootings at other locations.

"We need to act."

At an event in North Carolina, President Joe Biden continued to call for U.S. lawmakers to enact federal legislation addressing the nation's gun crisis.

"So I again call on Congress to pass the assault weapons ban, as it should not be a partisan issue. It's a common sense issue. They have to act now. People say 'why do I keep saying this if it's not happening?' Because I want you to know who isn't doing it, who isn't helping. To put pressure on them."

According to the K-12 School Shooting Database, Monday's attack in Nashville marked the 90th school shooting in the U.S. so far this year.