Grief-stricken Nashville residents came together for a vigil Wednesday to mourn three 9-year-old children and three adults killed in the mass shooting at a private Christian school.
First lady Jill Biden was in attendance as community members honored the victims, prayed and shared in the heartache. Singer-songwriter Sheryl Crow performed her song "I Shall Believe" to the grieving crowd.
"Just two days ago was our worst day," Mayor John Cooper said, opening the citywide vigil. "Our heart is broken. Our city united as we mourn together," he added, asking community members to join hands.
Metro Nashville Police Chief John Drake, who has become a familiar face providing updates on the investigation, told the crowd that a school shooting, like the one officers faced at The Covenant School on Monday, is a moment officers have trained for but hoped would never come.
"Our police officers have cried and are crying with Nashville and the world. I have cried and continue to cry and I have prayed for Nashville as well," Drake said, thanking the officers who rushed into the building and the other first responders who provided emergency care to the victims.
As the community grieves, police continue to work to answer the yet unanswerable: Why did 28-year-old Audrey Hale decide to storm into a private Christian school and murder three children and three adults?
Drake has said police have met with Hale's parents and school officials and have yet to uncover any specific issues or problems in the attacker's past.
RELATED: Nashville school shooting: Timeline of events leading up to attack that killed 6
"As of right now, we don't have any indication there was any problems at the school or at home," Drake told CNN on Wednesday. "We can't confirm any type of problems at this time."
The deadly rampage Monday morning at Covenant lasted about 14 minutes before the shooter was shot and killed by police. The assailant killed three 9-year-olds as well as a custodian, a substitute teacher and the head of the school.
The massacre marked the 19th shooting at a school or university in just the past three months that left at least one person wounded, a CNN count shows. It was among 130 mass shootings this year in the US with at least four wounded, excluding the shooting, and it was the deadliest US school shooting since last May's massacre in Uvalde, Texas, left 21 people dead.
A Nashville city councilman also said a witness told him the head of The Covenant School, Katherine Koonce, spent her last moments trying to protect the children in her care.
"The witness said Katherine Koonce was on a Zoom call, heard the shots and abruptly ended the Zoom call and left the office. The assumption from there is that she headed towards the shooter," Councilman Russ Pulley said. He did not identify the witness.
Drake, the police chief, said he can't confirm how Koonce died but said, "I do know she was in the hallway by herself. There was a confrontation, I'm sure. You can tell the way she is lying in the hallway."
Brink Fidler, who runs the company that did an active shooter training at the school, told CNN that Koonce had been adamant about training school staff on how to respond during an active shooter situation.
Fidler, who did a walk through of the school with officials Wednesday, said all of the victims who were struck by gunfire had been in an open area or hallway.
"The only victims this shooter was able to get to were victims that were stuck in some sort of open area or hallway," Fidler said. "Several were able to evacuate safely. The ones that couldn't do that safely did exactly what they were taught and trained to do."
Fidler said the shooter fired multiple rounds into several classrooms but didn't hit anyone inside the classrooms, "because the teachers knew exactly what to do, how to fortify their doors and where to place their children in those rooms."
Art instructor describes shooter's recent social media posts
A college art instructor who taught the shooter told CNN that Hale once had an outburst in class and appeared to be "suffering" in social media posts over the past year.
Maria Colomy, the instructor, taught Hale for two semesters in 2017 at Nossi College of Art & Design in Nashville. On the first day of class, Hale could not figure out how to set up a password, became upset and had to leave the classroom, Colomy told CNN. It was Hale's only outburst, she said.
Colomy described Hale as a small, quiet student and described Hale's work as "whimsical" and "childlike."
ALSO SEE: Nashville police officer who helped take down school shooter grew up in Chicago
"I could have seen (Hale) doing children's books for a living," Colomy said.
Colomy followed Hale on Facebook, and for the past year Hale's posts grieved the apparent death of a former girls' basketball teammate, the instructor said.
"The only thing I would see (Hale) post would be about this girl," she said.
It was around this time that Hale expressed on Facebook a desire to use he/him pronouns and the name Aiden. Police have said Hale was transgender.
"From what I saw on (Hale's) social, (Hale) was suffering," Colomy said.
The shooter's posts give more details
In Monday's attack, the killer targeted the school -- which the shooter attended as a child -- but it's believed the victims were fired upon at random, police said. Police have said they do not yet know of a motive but noted the attack was closely planned.
Hale had been under care for an emotional disorder and legally bought seven guns in the past three years, keeping them hidden in her home from her parents, Drake said.
Tennessee does not have a "red flag" law that would allow a judge to temporarily seize guns from someone who is believed to be a threat to themselves or others. Even so, Drake said they did not know about Hale's issues, and there is yet no evidence that Hale was believed to be a threat prior to this week.
"Law enforcement was never contacted," he said. "She was never committed to an institution."
The shooter is believed to have had weapons training, police spokesperson Don Aaron told CNN.
Drake also said officials are combing through a notebook of writings from Hale to learn more. Hale had written extensively in a personal notebook about the shootings, including detailed maps of the school, and had scouted a second possible attack location in Nashville, Drake said.
The attacker was "prepared for confrontation with law enforcement, prepared to do more harm than was actually done," Drake said Monday.
Hale's childhood friend told CNN on Tuesday the killer sent her disturbing messages minutes before the attack, saying "I'm planning to die today" and it would be on the news.
Hale graduated from Nossi College of Art & Design last year, the president of the school confirmed to CNN. Hale worked as a freelance graphic designer and a part-time grocery shopper, a LinkedIn profile says.
Police have referred to Hale as a "female shooter," and later said Hale was transgender. Hale used male pronouns on a social media profile, a spokesperson told CNN when asked to clarify.
Police fatally shot attacker, bodycam footage shows
Bodycam footage from the officers and surveillance video released by police provided a timeline of the attack and response.
Armed with three firearms, the shooter entered the school by firing at glass doors and climbing through to get inside, then walked down the hallways and pointed an assault-style weapon, surveillance video released by police shows.
The first call about the shooting came in at 10:13 a.m., and police rushed to the school, arriving at 10:24 a.m., according to the police chief.
RELATED: Nashville school shooting: Gov says it's not time to talk gun laws; suspect hid weapons from parents
Police on Tuesday released body-camera footage from the two officers who opened fire on the shooter after rushing into the school on Monday. The footage shows a group of five officers entered the school amid wailing fire alarms and immediately went into several empty classrooms rooms to look for the suspect.
As they cleared the rooms, officers heard gunfire from upstairs and rushed up to the second floor. An officer armed with an assault-style rifle fired multiple times at a person near a large window, who dropped to the ground, the video shows.
Another officer then appeared to shoot the person on the ground four times with a handgun, yelling, "Stop moving!" The officers then approached the person, moved a gun away and radioed, "Suspect down! Suspect down!"
The shooter was dead at 10:27 a.m., police said.
As a private school operated by a church, there was no school resource officer assigned by the city to guard the school, according to Aaron, the police spokesman.
Asked about the roughly 11-minute gap between when police received the first call of an active shooter and when officers arrived at the school, the police chief told reporters, "From what I've seen, I don't have a particular problem with it. But we always want to get better. We always want to get there in 2 or 3 minutes, and so there's a lot of things that could have happened -- traffic was locked down, etc."
The quick law enforcement response in Nashville stands in notable contrast with the delay in Uvalde, Texas, of more than an hour before authorities confronted and killed the gunman -- a lag that revived a nationwide conversation about the use of force during shootings in public places, especially schools.
9-year-old victim was 'incredibly smart,' aunt says
The victims of the shooting included three 9-year-old students: Evelyn Dieckhaus, William Kinney and Hallie Scruggs, the daughter of lead church pastor Chad Scruggs.
Hallie's aunt Kara Arnold said the 9-year-old had "a love for life that kept her smiling and running and jumping and playing and always on the go."
"To watch her these past 9 years has been a gift and a privilege," Arnold wrote on Facebook. "I have often longed for a daughter and Hallie embodied all of those things I'd want in my own little girl."
She said Hallie and her son Chip were almost the same age and were very close.
"When they were together no one else existed and we would rarely know where they were or what they were up to," she wrote, adding that they were usually involved in some sort of mischief.
"She was incredibly smart, feisty enough to keep up with her 3 brothers and my 4 boys, a love for life that kept her smiling and running and jumping and playing and always on the go," Arnold wrote.
Arnold told CNN that she is on her way to Nashville to be with her brother and sister-in-law.
RELATED: Body camera video released from police who fired at Nashville school shooter; 3 kids, 3 adults dead
"I don't have the words to address this tragedy. I'm in shock and my boys and Adam and I can't even comprehend that she's gone," she wrote. "We are grieving so deeply. And for my brother and sister in law and my nephews who are living the most unspeakable nightmare. We hurt with you and wish we could take your hurt away."
William, another of the children killed, had an "unflappable spirit," friends of the Kinney family shared on GoFundMe.
"He was unfailingly kind, gentle when the situation called for it, quick to laugh, and always inclusive of others," they wrote.
Will had two sisters and enjoyed spending time with his family and friends. "Our hearts are broken for his family as they try to find their way forward," the friends said.
Evelyn's family appreciates all the love and support they've received and are asking for space as they grieve, according to a family statement obtained by CNN affiliate KMOV.
"Our hearts are completely broken. We cannot believe this has happened," the statement said. "Evelyn was a shining light in this world."
The adults killed in addition to Koonce, 60, were Cynthia Peak, 61, a substitute teacher, and Mike Hill, a 61-year-old custodian, police said.
Peak was best friends with Tennessee first lady Maria Lee and was supposed to go to the Lees' home for dinner Monday evening, Tennessee Gov. Bill Lee said in a video statement Tuesday.
RELATED: Actress Melissa Joan Hart describes helping children flee campus after Nashville school shooting
"Maria woke up this morning without one of her best friends, Cindy Peak," the governor said. "Cindy and Maria and Katherine Koonce were all teachers at the same school and have been family friends for decades."
Hill was a father of seven children and grandfather to 14 who loved to cook and spend time with his family, his family said in a statement obtained by CNN affiliate WSMV. Evelyn's family called her "a shining light in this world."
The city has set up a fund to help support the survivors of the shooting, Mayor Cooper said.
(The-CNN-Wire & 2022 Cable News Network, Inc., a Time Warner Company. All rights reserved.)