Pinkerton Security Guard Fatally Shoots 'Patriot Rally' Protester During Altercation

A private security guard was arrested in Denver, Colorado on Saturday after a shooting at a [...]

A private security guard was arrested in Denver, Colorado on Saturday after a shooting at a confrontational protest. According to a report by local NBC News affiliate 9NEWS, 30-year-old Matthew Dolloff is being held on suspicion of first-degree murder, but has not yet been formally charged. Dolloff works for the Pinkerton National Detective Agency, and was contracted for 9NEWS security at the event.

The deadly shooting took place just outside of the Denver Art Museum, within sight of a police surveillance camera. The Denver Police Department has footage of the shooting, and they told reporters it started with a verbal altercation at around 3:50 p.m. local time. Protesters were leaving the area when someone sprayed pepper spray at an opposing protester within the crowd. It was then that a shot was fired — police say by Dolloff, who was taken into custody and is still being held at the Denver Downtown Detention Center.

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

The confusing scene involved a "Patriot Rally" and a counter-protest, which was affiliated with the Black Lives Matter and had the label "AntiFa" attached to it. The police have not provided specifics on how the two groups clashed, how fighting broke out or which of the two groups was responsible. However, photos published by The Denver Post show the man with pepper spray to be wearing a "Blue Lives Matter" shirt. He appears to slap the shooter before taking out his pepper spray.

The shooter wore a face mask, so he was hard to identify, though he could have been Dolloff. The complete set of photos then show him holding dropping to his knees and complying with police, who wore full riot gear in military colors.

The "Patriot Rally" organizer John Tiegen gave a radio interview on Friday, saying: "I'm not going in there to do violence, but I'm going to be prepared to do violence." A man told the post that the shooting victim was his father, Lee Keltner, a local hat-maker.

"The Denver Police Department respects the right to peacefully assemble," the DPD said in a statement. "Those who participate in protests, demonstrations, marches, or other gatherings, as protected by the First Amendment, are reminded to do so in a lawful manner. Individuals who choose to act outside of local, state and federal law, will be subject to citation or arrest."

Police initially arrested a 9NEWS producer along with Dolloff, but released him with no charges shortly after. The shooting is still under investigation.