Aat a private religious grade school in Nashville, Tennessee, left three adults and three 9-year-olds dead on March 27.
The shooter, identified by police as former student Audrey Hale, 28, was killed by police at the scene.
The shooting and the possible motive remains under investigation.
Reports were first made of a shooting at The Covenant School, a private Christian school that teaches pre-K through sixth grade, on morning of March 27. Surveillance video showed the shooter was able to get into the school by shooting out a side door. The shooter then traversed the building, going to the second floor and "firing multiple shots."
It's not clear when the six victims were killed or how they encountered the shooter.
The shooter was killed within 14 minutes of the first report of the shooting, police said, an action that likely "saved ... many lives,".
The shooting was a "targeted attack," officials. The shooter, a former student at The Covenant School, may have had "some resentment for having to go to that school," Nashville Police Chief John Drake told "CBS Mornings."
However, the students and adults killed — including a custodian, a substitute teacher and the head of the school — were likely not specifically targeted, authorities told CBS News.
"We have no evidence that individuals were specifically targeted," said Don Aaron, the director of media relations at the Metropolitan Nashville Police Department. "This school, this church building was a target of the shooter, but we have no information at present to indicate that the shooter was specifically targeting any one of the six individuals who were murdered."
What we know about the victims
The six victims were.
The three children are Evelyn Dieckhaus, Hallie Scruggs and William Kinney, all 9 years old. Scruggs was the daughter of Chad Scruggs, the senior pastor at Covenant Presbyterian Church, which is associated with the private school.
The adults killed were identified as head of school Katherine Koonce, 60, substitute teacher Cynthia Peak, 61, and custodian Mike Hill, 61.
Body camera footage released by police shows a female adult telling arriving police officers that some students were in lockdown during the shooting. According to the school's website, The Covenant School has 33 teachers and up to 210 students. Other students were brought to a reunification center after the shooting, police said.
U.S. flags at federal properties were flown at half-staff through March 31 in honor of the six victims. A large memorial at the school with flowers, stuffed animals and candles.
A former studentthat Koonce was "a champion for all students" who was full of life and "had a lot more to give."
"I'm representing a lot of people when I say she pulled us across the finish line oftentimes after we quit," Barrett Severance said.
The family of Hill said in a statement shared with CBS' Nashville affiliate that the 61-year-old had worked at the school for 14 years.
"We would like to thank the Nashville community for all the continued thoughts and prayers. As we grieve and try to grasp any understanding of why this happened, we continue to ask for support," the family wrote. "We pray for the Covenant School and are so grateful that Michael was beloved by the faculty and students who filled him with joy for 14 years. He was a father of seven children ... and 14 grandchildren. He liked to cook and spend time with his family."
What we know about the shooter
The shooter was identified by police on March 27 as 28-year-old Audrey Hale, of Nashville. No motive has been determined.
The shooter had three weapons at The Covenant School, police said, but had from five local gun stores. The shooter lived with the shooter's parents and hid the guns from them. , the shooter's parents believed that their child had one gun that had been sold. They did not know about the other purchases and felt that Hale should not own weapons.
Police said the shooter had been receiving treatment for an "emotional disorder" that had not been reported to authorities. Tennessee does not have a "red flag law" that could give police the authority to remove weapons from a person, Drake told CBS News.
"As it stands, we had absolutely no idea, actually, who this person was," Drake said.
On April 3, police said that writings found in the shooter's vehicle and bedroom indicated that the attack was"over a period of months."
Police have said that the shooter was extremely prepared for the killings, with a "manifesto" and other details found in the shooter's home.
Drake said on "CBS Mornings" that authorities found a booklet that detailed the entry point into the school, the weapons the shooter used and the clothing that the shooter wore during the attack.
The maps found were detailed, Drake said, with possible entry routes and surveillance notes.
"There's quite a bit of writing to it," Drake told reporters March 28. "I have not read the whole manifesto. Our team and the FBI have been working on this."
Drake said that the shooter may have had other targets, including a local mall. Maps found at the shooter's home turned up more maps "pertaining to maybe some thinking about some other incidents," he said.
"We strongly believe there was going to be some other targets, including maybe family members, and one of the malls here in Nashville," Drake said. "And that just did not happen."
Editor's note: An earlier version of this story incorrectly identified The Covenant School as a Catholic school. It is a Christian school.
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