Louisville police have released the dramatic 911 calls from Monday's mass shooting inside a bank.

One woman who called 911 said about eight or nine people have been shot. She said she was hiding in a closet in the first-floor conference room.

She told the dispatcher she knew the shooter, who worked with her.

Loud gunshots are heard booming in the background as the employee recounted what was happening.

The dispatcher told the woman to stay quiet and stay where she was. Whispering, she told the dispatcher there was a lot of blood.

The mother of the suspected gunman, 25-year-old Connor Sturgeon, called 911 to say her son's roommate called her and was concerned.

"He apparently left a note," she said.

"He's never hurt anyone, he's a really good kid," Sturgeon's mother told the dispatcher. "I don't know where he would've gotten a gun."

"I know he doesn't own any guns!" she told the dispatcher.

Sturgeon, who was killed by police at the scene, bought the AR-15 used in the attack legally on April 4 in Louisville, according to police.

Nickolas Wilt, the rookie Louisville police officer shot in the head while responding to Monday's shooting at Old National Bank, is "slowly improving," city authorities told ABC News Wednesday morning.

Wilt remains in critical condition, however. He was the only victim still listed in critical condition.

-ABC News' Will McDuffie

The family of the suspected gunman, 25-year-old Connor Sturgeon, issued a statement Monday night expressing their sorrow, also saying "there were never any warning signs or indications he was capable of this shocking act."

"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 Sturgeon family said. "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."

"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," the family said. "While we have many unanswered questions, we will continue to cooperate fully with law enforcement officials and do all we can to aid everyone in understanding why and how this happened."

-ABC News' Alondra Valle

Louisville Deputy Chief Paul Humphrey provided a timeline of the police response to Monday's shooting while sharing body camera footage from the responding officers:

--8:38 a.m.: Officers dispatched.

--8:41 a.m.: Officers Nickolas Wilt and Cory Galloway pull up to an entrance to the bank. Gunshots are immediately fired in their direction, forcing them to back up the car.

--8:42 a.m.: They exit the vehicle.

--8:44 a.m.: Wilt is struck and officers return fire. When Wilt is struck, Galloway is heard yelling, "He’s down! Get the officer!”

--8:45 a.m.: After a short barrage of gunfire, officers make entry to the bank and confirm the suspect is down.

-ABC News' Will McDuffie

There have been at least 15 mass shootings in the U.S. in the first 10 days of April, including Monday morning's shooting in Louisville, according to the Gun Violence Archive.

So far this year, the nation has seen at least 146 mass shootings.

The Gun Violence Archive defines a mass shooting as at least four people shot, not including the suspect.

“It feels like every day in this country we are totally consumed by yet another mass shooting. Nowhere else in the developed world do people wake up to this preventable horror every single morning," Kris Brown, president of the Brady Center to Prevent Gun Violence, said in a statement Monday. "Whether it's a bank, a school, a supermarket, or a church, Americans no longer feel safe in their communities. And Americans are increasingly tired of living in fear of being a victim of a mass shooting."

“It does not have to be this way," Brown said. "But until the gun industry no longer has a vice grip on our elected officials, this will continue to be our daily reality."

-ABC News' Ahmad Hemingway