Audrey Hale, a 28-year-old former Covenant School student who killed six people at the school Monday, carefully planned the attack, according to officials.

Hale’s parents, who lived with the shooter, said Hale was under a doctor’s care for an “emotional disorder,” Nashville Police Chief John Drake said at a news conference Tuesday.

The shooter had various writings and maps of the school, as well as drawings of how to enter, Drake said.

Police know Hale left home Monday morning with a red bag and that Hale’s mother did not know weapons were inside, Drake said.

What we know about the Nashville shooter Audrey Hale© Provided by CNN

This undated picture provided by the Metro Nashville Police Department shows Audrey Elizabeth Hale. – Metro Nashville Police

Authorities continue to work to answer questions about who Hale was and the motive behind the school shooting. While the shooter’s gender identity is unclear, police told CNN Hale was assigned female at birth and that Hale used “male pronouns” on social media.

The shooter sent a message to a former classmate before the shooting

Less than 20 minutes before the shooting, Hale sent an eerie Instagram message to Averianna Patton, a former basketball teammate who told CNN’s Don Lemon she’s “still trying to process it all.”

“I knew her well when we were kids,” Patton told Lemon on “CNN This Morning” on Tuesday. Patton, now a Nashville radio host, said she hasn’t had a relationship with the suspect since they were children and has only ever referred to Hale as Audrey or “she.”

“I didn’t know the adult … I don’t know that side of her,” Patton told Lemon when asked about the suspect.

Patton said she received the Instagram message at 9:57 a.m., which read, “One day this will make more sense. I’ve left more than enough evidence behind. But something bad is about to happen,” according to screen grabs sent to CNN affiliate WTVF.

Patton said she was not sure why Hale reached out. “I’m asking God the same question,” Patton told Lemon.

When they were on the team together, Patton said, Hale was “very quiet, very shy,” and they joked around together.

“We got to see her grow in her skill on the court,” Patton told CNN on Tuesday evening. “We did really good that year. We went all the way to the city (championships), so it was a really good year for us. We had a real camaraderie.”

Hale graduated from a Nashville art college

Hale graduated from Nossi College of Art & Design in Nashville last year, the school’s president confirmed to CNN. A LinkedIn profile says Hale worked as a freelance graphic designer and a part-time grocery shopper.

An online portfolio that appears to show a collection of Hale’s work includes images of professional logos, cartoon animals and an apparent self-portrait. One image included the phrase, “To Be A Kid (forever and ever).”

Hale won “Most Improved” and “Class Participation” awards from Nossi, according to web posts by the college.

A former vice president of the college, Byron Edwards, described Hale as, “… the sweetest little thing. I’m just shocked. My wife and I have been crying all day about it,” adding that Hale “was really shy and really good.”

Former teacher: Shooter wrote on Facebook about romantic partner’s death

The shooter also had posted on Facebook sometime in the past two years about the death of a romantic partner, as well as a request to be referred to by the male name Aiden and with male pronouns, a former teacher told The New York Times.

Hale was transgender, police have said.

The shooter wrote about missing the partner and posted photographs of the two playing basketball together, said Maria Colomy, who taught Hale at the Nashville art college in 2017.

“She had been openly grieving about that on social media, and during the grieving is when she announced that she wanted to be addressed as a male,” Colomy told the Times on Tuesday. The shooter’s Facebook account has been taken down.

Colomy also recalled how Hale began to cry on the first day of class at the art college while struggling to create a password for the online student portal, the Times reported. Colomy asked the student if it would help to step out for a second, and Hale did, the teacher said.

It was the only time the student showed such extreme emotion in class, but Colomy told the Times it was an unusually strong reaction over a mundane problem.

CNN’s Curt Devine, Audrey Ash and Melissa Alonso contributed to this report.