A day after the fatal shootings at the Covenant School in Nashville, police are beginning to uncover the motive of the shooter, who may have harbored resentments of the Presbyterian school prior to the carefully planned attack.

The three children who were killed were Evelyn Dieckhaus, Hallie Scruggs and William Kinney, all of whom were nine years old. A 61-year-old substitute teacher, Cynthia Peak; a 61-year-old custodian, Mike Hill; and a 60-year-old school official, Katherine Koonce, were also killed.

At a press conference Tuesday afternoon, Nashville Police Chief John Drake said that the shooter, 28 year old Audrey Hale, was being treated for an emotional disorder.

Additionally, Hale’s parents were unaware that the shooter, who lived at their home, had purchased seven firearms from five area gun stores. Mr. Drake said that had the police known of the shooter’s intention’s they would have “tried to get those weapons.”

“As it stands, we had absolutely no idea actually who this person was,” Mr. Drake said.

Monday, Mr. Drake told reporters that the preliminary investigation into the shooting suggested that the school was targeted.

“We have a manifesto, we have some writings that we’re going over that pertain to this date, the actual incident,” Mr. Drake said. “We have a map drawn out of how this was all going to take place.”

Mr. Drake also told NBC news that detectives have reason to believe that the shooter had “some resentment for having to go to that school.”

“I was literally moved to tears to see this and the kids as they were being ushered out of the building,” Mr. Drake said. “When we send our kids to school, or to any place of safety, we expect them to live, learn, have fun and come back from that day’s experience. We don’t anticipate things like this.”

The shooter was armed with an AR style assault weapon as well as a handgun.

According to Me. Drake, a search of the shooter’s home found “maps drawn of the school, in detail” including “surveillance, entry points, et cetera” as well as a manifesto.

Mr. Drake also said that there was another location mentioned in the materials that police recovered, although details are not public.

Police did not elaborate further on the motive of the suspect but said that the shooter “targeted random students” and that “Whoever she came in contact with, she fired rounds.”

The police identified the 28 year-old shooter as Audrey Hale, although they later announced that Hale had recently come out as transgender and had reportedly asked family members to use he/him pronouns. Hale also referred to herself as both Audrey and Aiden.

The police also found “additional material written by Hale” in a Honda fit that Hale drove to the school.

In messages between Hale and a friend, Averianna Patton, sent over instagram and obtained by News Channel 5 Nashville, Hale told a friend that “I’m planning to die today.”

“You’ll probably hear about me on the news after I die,” Hale wrote. “This is my last goodbye.”

In the messages, Hale indicated that the motive for the shooting would become clear after people were able to read the material left behind.

“One day this will make more sense,” Hale wrote. “I’ve left more than enough evidence behind — but something bad is about to happen.”

Ms. Patton said that she called the Suicide Prevention Help Line that morning as well as the Nashville Davidson County Sheriffs Office. 

“I called Nashville’s non-emergency line at 10:14 a.m. and was on hold for nearly seven minutes before speaking with someone who said that they would send an officer to my home,” Ms. Patton said. “An officer did not come to my home until 3:29 p.m..”

Ms. Patton said that she believed that officials should have acted with more urgency after she reached out to officials concerning Hale’s messages.

“After phone calls from friends and Audrey’s name was released as the shooter at Covenant Nashville school, I learned that Audrey was the shooter and that she had reached out to me prior to the shooting,” Ms. Patton said. “My heart is with all of the families affected and I’m devastated by what has happened.”