Some things to remember when trying to judge details from a camera:
1) due to the 2d nature of cameras and lens properties, distance will be distorted and sometimes be difficult to judge accurately.
2) camera shake even with image stabilization software can make viewing difficult and reduces detail much more than the human eye in real-time.
3) a camera video played back on a monitor does NOT equal the video resolution, frame speed, or effective image size of the human eye in real-time.
Trying to contradict or judge the cop because you assume that because you can't tell it was a gun the suspect dropped and picked up from the video and therefore assume he had the same faulty view as you is sloppy thinking.
The facts as shown on this video are simple:
1) Cop shows up to a call of threatened domestic violence. Suspect threatened to shoot his girlfriend.
2) Cop asks the suspect if he has any weapons or "anything else that will hurt me". The suspect LIES and says "no".
3) Cop starts search.
4) Suspect flees.
Important to note that regardless of the allegation that the cop is claimed to have felt the gun, the information on the video shows only that the cop chases a suspect that has claimed to have no weapon... and the cop does not fire at this time.
5) During the chase the suspect drops what is confirmed, and RIGHTFULLY claimed by the cop from what he saw, to be a gun and picks it up.
Important: Whether the cop believed the earlier lie that he was unarmed, or felt and SUSPECTED that he had a gun but there was doubt... there is no doubt at this point that the suspect is armed, agitated, and dangerous.
6) Cop immediately fires and kills suspect.
Important: What could possibly make anyone think that if a suspect in a confrontation with a cop suddenly grabs what a cop knows to be a gun that the cop won't shoot them dead?
Justified. This is a slam dunk case.