DENVER (NewsNation Now) — A private security guard working for a Denver TV station is behind bars and accused in the deadly shooting of another man during dueling protests, police said Sunday.

Matthew Dolloff, 30, was booked into jail for investigation of first-degree murder following the clash Saturday afternoon in Civic Center Park.

Authorities have not identified the man killed, but family members and friends told NewsNation affiliate KDVR that his name was Lee Keltner. His son told the Denver Post that Keltner was a 49-year-old U.S. Navy veteran who operated a hat-making business in the Denver area.

“He wasn’t a part of any group,” Johnathon Keltner told the newspaper. “He was there to rally for the police department and he’d been down there before rallying for the police department.”

A video by Brian Loma via TMX.news captured the shooting from a distance and the arrest of a suspect. A “Patriot Muster” rally and a “BLM-Antifa Soup Drive” had just ended at Civic Center Park when officers in the area received reports of shots fired around 3 p.m., KDVR reported.

Denver Police Division Chief Joe Montoya said a man suffering from a gunshot wound was on the ground when police arrived at the scene. Authorities provided aid until the victim was transported to the hospital, where he was pronounced dead.

Two suspects were taken into custody after the shooting. Montoya said only one remained in custody and police later identified the suspect as a private security guard with no affiliation to Antifa.

Two guns and a can of mace were retrieved from the scene, Montoya said.

A video obtained by KDVR shows a heated argument between two men just before the shooting occurred, and one of them carried a mace can in hand. The man with the mace appears to walk away, then sprays the mace and is shot.

A decision on any charges will be up to the Denver District Attorney’s Office, police said. A spokesperson for District Attorney Beth McCann said Sunday that the arrest affidavit in the case remained sealed and referred further questions to the police.

It was not immediately clear if Dolloff had an attorney who could comment on his behalf.

The shooting occurred beneath a city surveillance camera, and police said they have footage of the incident, KUSA-TV reported.

KUSA said it had hired the guard through the Pinkerton security firm.

“It has been the practice of 9NEWS for a number of months to hire private security to accompany staff at protests,” the station said.

Attorney Chris Decker told NewsNation affiliate KDVR that in Colorado, a person can protect themselves or someone else from what they reasonably believe to be the use or imminent use of unlawful force.

“There are no clear and absolute bright lines with the doctrine of self-defense,” he said. “No one can really tell until or unless that were charged and a jury would determine the reasonableness of the circumstances.”

Security guards in Denver are supposed to be licensed, with additional endorsements needed to carry a firearm or operate in plainclothes, according to rules for the industry adopted by the city in 2018.

Representatives of Pinkerton did not immediately return email and telephone messages for comment.

The Associated Press and NewsNation affiliate KDVR contributed to this report.