LOUISVILLE, Ky. -- The mother of the shooter who killed five people at Old National Bank in Louisville, Kentucky, on Monday called 911 after hearing secondhand that her son had a gun and was heading toward the bank, according to 911 calls released by police Wednesday.
"My son might be (redacted) has a gun and heading to the Old National on Main Street here in Louisville," she said. "This is his mother. I'm so sorry, I'm getting details secondhand. I'm learning about it now. Oh my Lord."
She said her son "apparently left a note" about the incident and she expressed her shock and confusion.
"He's never hurt anyone, he's a really good kid," she said. "We don't even own guns. I don't know where he would have gotten a gun."
The call, which came in at 8:41 a.m. Monday, was one of a number of 911 calls released to the public Wednesday detailing the panic and fear during the mass shooting, in which the gunman, 25-year-old bank employee Connor Sturgeon, used a recently purchased AR-15-style rifle to shoot his coworkers and responding officers before he was shot dead by police.
The attacker livestreamed the gruesome assault, which took place about 30 minutes before the bank was set to open, authorities said.
Five people were killed, and three remained hospitalized as of Tuesday, including Nickolas Wilt, a 26-year-old rookie police officer who just graduated from the police academy 10 days earlier and was shot in the head.
The release of the files comes as officials in Louisville prepare to host a vigil at 5 p.m. to grieve the victims and as the gunman's family released a statement outlining his mental health challenges. Police on Tuesday also released dramatic police body camera footage showing the response to the shooting.
RELATED: Louisville shooting: Police release body cam footage from shooting
The attack was just one of more than 145 shootings reported in the US this year with at least four people shot, excluding the shooter.
Bank employee told 911 she saw shooting on video
According to the audio files, the first caller to 911 came from a woman who works at a different branch of Old National Bank and witnessed the shooting on video.
"How do you know you have an active shooter on site?" the dispatcher asked.
"I just watched it. I just watched it on a Teams meeting. We were having a board meeting," she said. "I saw somebody on the floor. We heard multiple shots and people started saying 'Oh my God,' and then he came into the board room."
Another caller, speaking in a whisper, said she works at the bank and is hiding in a closet. While on the line, several gunshots can be heard in the background.
"I know who it is," the caller said. "He works with us."
Other 911 calls came from another bank employee, a person who works at a nearby business and someone who was driving down the street and saw the gunman.
"He was kind of like jogging around like he was trying to get somewhere in a hurry," the caller said.
Staff members were holding their morning meeting in a conference room when the gunman opened fire, bank manager Rebecca Buchheit-Sims told CNN.
She said the massacre "happened very quickly." Buchheit-Sims attended the staff meeting virtually and watched in horror as gunfire exploded on her computer screen.
"I witnessed people being murdered," she told CNN. "I don't know how else to say that."
Family says gunman had depression
In a statement released Wednesday, the gunman's family laid out his mental health challenges but said they never saw any warnings signs of such an attack.
"While Connor, like many of his contemporaries, had mental health challenges which we, as a family, were actively addressing, there were never any warning signs or indications he was capable of this shocking act," Connor Sturgeon's family said in a statement to CNN affiliate WDRB.
The family said it has many "unanswered questions" and is cooperating with the investigation.
"No words can express our sorrow, anguish, and horror at the unthinkable harm our son Connor inflicted on innocent people, their families, and the entire Louisville community," the statement read.
"We mourn their loss and that of our son, Connor. We pray for everyone traumatized by his senseless acts of violence and are deeply grateful for the bravery and heroism of the Louisville Metropolitan Police Department."
A former high school classmate of Sturgeon's who knew him and his family well said he never saw any "sort of red flag or signal that this could ever happen."
"This is a total shock. He was a really good kid who came from a really good family," said the classmate, who asked not to be identified and has not spoken with Sturgeon in recent years. "I can't even say how much this doesn't make sense. I can't believe it."
It's still not clear what provoked the shooter to go on the deadly rampage. Sturgeon used an AR-15-style rifle -- the choice weapon of many US mass shooters -- he'd legally bought six days before the attack, police have said.
Kentucky has some of the least restrictive gun laws in the US: no "Red flag" laws, no universal background checks, permitless concealed carry and no waiting period between buying a firearm and taking possession of it. Those relaxed gun laws, experts say, help explain why the state has a firearm death rate higher than the national average, according to the CDC.
What the body camera footage shows
On Tuesday, Louisville police released bodycam video and bystander footage showing the officers' response to the mass shooting.
The public footage begins with a video from Officer Wilt, who drove up to the scene with his training officer, Cory "CJ" Galloway.
As Wilt ran toward the gunshots that officers faced upon arrival, he was shot in the head, police said. The released version of Wilt's footage cuts off before he is shot.
Galloway's body camera footage shows him taking fire and then scrambling down some stairs to a safe position behind a planter. He tells other officers he can't see the gunman but notes the gunman is shooting through windows in the front of the bank, the video shows. At some point, Galloway was also shot.
The gunfire shattered the bank's lobby glass windows, giving officers a view of his location, Deputy Chief Paul Humphrey said.
As other officers arrived on scene, Galloway shot and killed the gunman from the steps in front of the bank, the video shows.
"I think I got him down! I think he's down!" Galloway said, the video shows. He then advanced toward the building and directed others to check on his fallen colleague. "Suspect down. Get the officer!"
The bystander footage, also released by police, was filmed across the street from the bank. The video shows Galloway taking cover behind the planter with his gun raised and pointed toward the building as he tries to locate the gunman's position.
The entire situation -- from when the gunman began firing his assault weapon to when he was killed by police -- lasted for about nine minutes, according to Louisville police Lt. Col. Aaron Cromwell.
Shooting happened in one minute, official says
It took the assailant one minute to complete the bloodbath before he stopped and waited for police to arrive, according to footage of the massacre described by a city official to CNN.
The shooter had livestreamed the gruesome attack on Instagram. The video has since been taken down.
The Instagram video begins by showing an AR-15-style weapon, followed by a worker in the bank saying good morning to the gunman, the official said.
The gunman then tried to shoot her in the back but failed because the safety was on and the weapon still needed to be loaded, the official said. Once the shooter loaded the weapon properly and took the safety off, he shot the worker in the back, the official said.
The assailant then continued his rampage, firing at workers while they tried to outrun him, the official said. The shooter did not go to other populated floors of the bank, the official said.
Once the shooter finished firing, he sat in the lobby area that looks out onto the street, apparently waiting for police, the official said. Police arrived about a minute and half later, the official said.
Sturgeon had interned at the bank for three summers and been employed there full-time for about two years, his LinkedIn profile showed.
The assailant had been notified that he would be fired from the bank, a law enforcement source said Monday. However, the police chief told CNN's Abby Phillip on Wednesday there "was no discussion about [the shooter] being terminated, and of course he wasn't fired," prior to the shooting.
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