DENVER (CBS4)– Denver police have released the arrest affidavit for Matthew Dolloff, the private security guard who was arrested in the shooting death of Lee Keltner. The deadly shooting happened during dueling protests on Saturday in downtown Denver.

Matthew Dolloff (credit: Denver Police)

Dolloff, 30, was contracted as a security guard by 9News through the security company Pinkerton.

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According to the affidavit, Keltner was engaged in a verbal dispute with another protester and some witnesses believed the altercation would have become physical. Someone intervened in the argument and broke it up.

Police said that dispute was captured on Denver HALO cameras as well as cellphone video and digital photography from multiple witnesses.

Two men clash after dueling rallies in Downtown Denver on October 10 in Denver. The confrontation led to the man on the right fatally shooting the man on the left of the photo. The shooting happened as opposing rallies by far-right and far-left activists were ending. The shooter has been identified as Matthew Dolloff. He is being held for investigation of First Degree Murder in connection with this shooting. (Photo by Helen H. Richardson/MediaNews Group/The Denver Post via Getty Images)

According to the affidavit, review of the video shows that Dolloff became engaged in an altercation with Keltner while he was arguing with the other protester. Keltner was holding a can of OC spray, also known as oleoresin capsicum spray or pepper spray, at the time.

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That’s when Keltner and Dolloff faced each other, about 3:36 p.m., and Keltner struck Dolloff on the side of the head with an open hand. Dolloff is seen drawing a handgun from his waistband, aiming at Keltner and shooting once.

(Photo by Helen H. Richardson/MediaNews Group/The Denver Post via Getty Images)

Keltner discharged his OC spray as he collapsed to the ground.

Dolloff was taken into custody by officers while holding a semiautomatic handgun. Keltner was rushed to Denver Health where he was pronounced dead at 4:05 p.m.

(Photo by Helen H. Richardson/MediaNews Group/The Denver Post via Getty Images)

Dolloff appeared in court on Sunday and remains in custody on investigation of first-degree murder charges.

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LINK: Dolloff Arrest Affidavit

Jennifer McRae