Editor’s Note: For the latest on the Louisville bank shooting, follow our live updates and most recent coverage here.

CNN  — 

A 25-year-old bank employee opened fire at his workplace in downtown Louisville, Kentucky, Monday morning and livestreamed the attack that left five dead and eight others injured, authorities said.

The gunman was identified as Connor Sturgeon, an employee at Old National Bank, according to interim Louisville Metro Police Chief Jacquelyn Gwinn-Villaroel. He was killed by police after a shootout with authorities.

Four of the victims, who died Monday morning, were identified as Joshua Barrick, 40; Juliana Farmer, 45; Tommy Elliott, 63; and James Tutt, 64, the chief said. Later that evening, police said a fifth victim – 57-year-old Deana Eckert – also died.

Authorities initially said nine others were injured in the attack, including a 26-year-old police officer who graduated from the police academy just 10 days ago and was shot in the head. Five of those injured had gunshot wounds, a hospital spokesperson said. Later Monday night, police said Eckert, one of the injured victims, had passed away, bringing the death toll to five.

Two people embrace outside the building where a mass shooting happened in Louisville on Monday.

The mass shooting began at the Old National Bank on East Main Street just after 8:30 a.m. police said, about 30 minutes before the bank opens to the public. It happened during a morning employee meeting, with some appearing in person and others virtually, Rebecca Buchheit-Sims, a manager at the bank, told CNN. She watched from her computer as her coworkers were gunned down.

Officers got to the bank within three minutes of being dispatched and found the shooter was still firing, Louisville Metro Police Deputy Chief Paul Humphrey said. Officers got into a shootout with the gunman, killing him, Gwinn-Villaroel said.

Mayor Craig Greenberg thanked the “brave and heroic” first responders for their actions. “Without a doubt their actions saved lives,” he said.

In the aftermath of the shooting, a large police presence blocked off much of the downtown street. Shattered glass was strewn at the entrance of the Old National Bank, video from CNN affiliate WDRB shows.

Police step on shattered glass at the Old National Bank in Louisville, Kentucky, on Monday after a mass shooting.

The shooting is just the latest spasm of mass gun violence, a uniquely American phenomenon. There have been at least 145 mass shootings in the US this year, according to data from the Gun Violence Archive, which like CNN, defines a mass shooting as one in which at least four people are shot, excluding the shooter.

The gun used in the shooting was an AR-15-style rifle, a federal law enforcement source told CNN. The AR-15, a semi-automatic rifle, is the most popular sporting rifle in the US, and about 24.6 million people have owned an AR-15 or similarly style rifle, according to the 2021 National Firearms Survey.

The AR-15 and its offshoots have been the weapon of choice in many of the most heinous mass shootings in recent memory, including in the Sandy Hook school in Connecticut; an Aurora, Colorado, theater; a San Bernardino, California, holiday party; and a Buffalo, New York, supermarket. In Nashville, just two weeks ago, a shooter used an AR-15 style weapon and two other guns in a mass shooting at a private Christian elementary school, killing three adults and three 9-year-olds.

Gunman joined bank full time in 2021

The shooting was livestreamed on Instagram and has been taken down but not immediately after the shooting. Police are in possession of the video, according to the source.