This is the moment a Colorado hat-maker was shot dead by a Pinkerton security guard amid dueling protests in Denver.

The shocking sequence of photos captured at the Saturday demonstrations show the two men approach each other, and the victim — identified in a Facebook post by his mother as Lee Keltner — raising his left hand to the other’s face.

The suspect — who has been identified as Matthew Dolloff, a Pinkerton private security guard — then drew a handgun, while Keltner raised a canister of Mace and let loose a yellow mist of the choking spray, the photos show.

The frames then capture Keltner crumpling to the sidewalk, as the Mace slowly dissipates in the air.

Ultimately, authorities moved in to arrest Dolloff, who crouched to the sidewalk to give up his gun.

Denver police have said Dolloff will be charged with homicide.

Keltner’s mother said in her Facebook post that her son was protesting in defense of law enforcement, in defiance of anti-police protests nearby.