LOUISVILLE, Ky. >> Police body camera video released Tuesday showed the chaotic moments when police arrived at the scene of a mass shooting at a bank in downtown Louisville, as the shooter they couldn’t see from the street rained bullets down on them.

The videos, taken from two wounded officers’ lapels, offer a rare perspective of police officers responding to a massacre that killed five and injured eight others Monday. One, a rookie officer, was shot in the head within minutes of arriving at the scene, as his partner was grazed by a bullet and sought cover while still trying to take down the shooter.

Louisville Metro Police Department Deputy Chief Paul Humphrey walked reporters through edited footage and still photos at a new conference Tuesday and praised the responding officers for their heroism.

They received the call of a shooting at Old National Bank at 8:38 a.m., and the two officers arrived three minutes later, according to a chronology provided by police. They hadn’t even gotten out of the patrol car when the gunman began firing on them.

“Back up, back up, back up,” one officer shouted as gunshots thundered in the background.

One still image from surveillance video showed the 25-year-old shooter, who worked at the bank, holding a rifle, wearing jeans, a blue button-down shirt and sneakers, surrounded by broken glass inside the building. He had already shot numerous people inside, and police said he set up an ambush position to attack officers as they arrived.

The front doors were glass, elevated from the sidewalk, and because of the reflection, the officers could not see the shooter inside, Humphrey said. But he could see them.

Officer Cory Galloway retrieved a rifle from the trunk of the patrol car.

“Cover for me,” he said, and they reported to dispatch that there had been shots fired.

Galloway was training rookie Officer Nickolas Wilt, who had graduated from the police academy just 10 days earlier. The videos showed them walking up the stairs toward the front door when the gunman fired a barrage of bullets.

Wilt was shot in the head, though that was not captured on video. Galloway was grazed in the shoulder, police said. His body camera showed that he fell and then took cover behind a concrete planter at the bottom of the staircase leading to the building. Sirens from the dozens of police cars coming toward them wailed in the background.

“The shooter has an angle on that officer,” he said in the video recording. “We need to get up there. I don’t know where he’s at, the glass is blocking him.”

A video taken by a bystander across the street, which police also released Tuesday, showed him darting back and forth from one side of the planter to another, trying to get a shot at the gunman.

He waited, and as other officers arrived, more gunshots rang out and glass shattered.

Galloway fired toward the gunman at 8:44 a.m., three minutes after arriving.

“I think I got him down! I think he’s down!” he shouted. “Suspect down! Get the officer!”

He advanced into the building, and shards of glass crunched under his feet. The video then showed Galloway approaching the suspect, who lay on the ground inside the lobby next to a long rifle.

“I think you can see the tension in that video,” Humphrey said Tuesday. “You can understand the stress that those officers are going through. … They did absolutely exactly what they needed to do to save lives. Once officers arrived on scene, not another person was shot.”

Wilt was transported in the back of a police car to a hospital, Humphrey said. In the chaotic first minutes, police treated and triaged the victims inside. Humphrey said the ambulance service was short-staffed, so a police lieutenant drove the ambulance while emergency crews treated people at the scene.

Wilt was still in critical but stable condition Tuesday, according to University of Louisville Hospital Chief Medical Officer Dr. Jason Smith.

Two of the four wounded still in the hospital had injuries that were not life-threatening, Smith said.

Louisville Mayor Craig Greenberg said it was crucial to release the footage because “transparency is important — even more so in a time of crisis.”

Police Chief Jacquelyn Gwinn-Villaroel said at a news conference that bank employee Connor Sturgeon, 25, bought the AR-15 assault-style rifle used in the attack at a local dealership on April 4.

Armed with the rifle, Sturgeon killed his co-workers — including a close friend of Kentucky’s governor — while livestreaming the attack.

“We do know this was targeted. He knew those individuals, of course, because he worked there,” Gwinn-Villaroel said, but didn’t give an indication of a motive behind the shooting.

Gwinn-Villaroel praised the “heroic actions” of officers who engaged the shooter without hesitation when they arrived.

“They went towards danger in order to save and preserve life,” she said. “They stopped the threat so other lives could be saved. No hesitation, and they did what they were called do to.”

The shooting, the 15th mass killing in the country this year, comes just two weeks after a former student killed three children and three adults at a Christian elementary school in Nashville, Tennessee, about 160 miles (260 kilometers) to the south.

In Louisville, five Old National Bank employees were killed: Joshua Barrick, 40, a senior vice president; Tommy Elliott, 63, also a senior vice president; Jim Tutt Jr., 64, a commercial real estate market executive; Juliana Farmer, 45, a loan analyst; and Deana Eckert, 57, an executive administrative officer.

The mayor urged unity as the community processes its grief, over this shooting and the many other spasms of gun violence that have stunned this city.

“We’re all feeling shaken by this, and scared and angry and a lot of other things too,” Greenberg said. “It’s important that we come together as a community to process this tragedy in particular but not just this tragedy because the reality is that we have already lost 40 people to gun violence in Louisville this year.”