BREAKING: Trans Nashville school shooter had planned attack for 'months': police

In an update released by the Metropolitan Nashville Police Department (MNPD) on Monday, officials revealed that trans-identified shooter Audrey Hale planned the attack that killed 3 children and 3 adults "over a period of months," and that Hale fired 152 rounds from the time she shot her way into the school until Hale was killed by police.

MNPD wrote in a press release that the ongoing investigation continues to show that Hale acted alone.

In writing recovered from Hale’s vehicle and bedroom, Hale documented "planning over a period of months to commit mass murder at The Covenant School."

"The writings remain under careful review by the MNPD and the FBI’s Behavioral Analysis Unit based in Quantico, Virginia. The motive for Hale’s actions has not been established and remains under investigation by the Homicide Unit in consultation with the FBI’s Behavioral Analysis Unit," MNPD wrote.

MNPD noted that Hale "considered the actions of other mass murderers."

The investigation has revealed so far that Hale shot a total of 152 rounds from the time she shot her way into the school until the time police fatally shot Hale, 126 5.56 rifle rounds and 26 nine-millimeter rounds.

Officer Rex Engelbert fired a total of four 5.56 rounds from his rifle at Hale, and Officer Michael Collazo fired a total of four rounds from his department-issued nine-millimeter pistol.

On Monday, March 27, Hale entered the Covenant School in Nashville, Tennessee, where Hale was a former student, and fatally shot six people, including three nine-year-old students.

Since then, it has been revealed that Hale had at least seven firearms hidden in her family's home, whom were under the impression that Hale had previously sold the single firearm that she possessed. Hale had also been in treatment for an unspecified emotional disorder, and it has also been reported that she had "high-functioning autism."