Based on seeing the video, it seems an officer standing in front of the decedent is the one who drew/disarmed the weapon from the decedent's holster. This was under the arching body of another agent who was holding the decedent down. The man who shot him was standing behind him.
Despite all the outraged rhetoric on here, it does not seem reasonable to assume that the officer simply decided to murder the man out of anger, spite, bloodlust, and perceived immunity.
Rather, a dispassionate analysis of the scenario might suggest that the shooter only saw the weapon be drawn by an unknown hand, and not discerning that it was one of his fellow officers disarming the struggling man, instead believed that the struggling man had managed to draw his own weapon and was preparing to fire.
Given the facing of the struggling man and the shooting officer, it seems unlikely that his first fear was for his own life but rather for the lives of his comrades, and so he fired his weapon to remove the perceived threat to his fellow officers lives.
This explains exactly why he fired almost immediately after he saw the gun drawn. Not an extrajudicial execution as some are recklessly calling it, but a tragic example of having to make life and death decisions with an imperfect view of the ... battlefield for lack of a better term ... and the foolishness of getting in the way of armed men.
I tell my kids they have the right of way at the crosswalk but right of way is not going to save their life if the car doesn't see them, so look both ways and make sure cars are slowing down.
The same sense of caution should be used when deciding to get in the way of men, even good and lawful men, with guns.
It made sense to protest the Vietnam war or Iraq or Afghanistan in America, not in the war zone.
We have freedom of speech and the right to petition the government for redress of grievances, but do that from the sidewalk, in court, or before Congress, not in the line of fire of a police action. And I don't believe we have the right to block roads, scream in the faces of law enforcement or military personnel, or impede them in the fulfillment of their lawful duties which these immigration enforcement actions are.