The second before the cop shoots, the (alleged) robber appears to be pointing his left hand directly at him. Not sure if the gun is still in his right hand at that moment, but it certainly looked like a threatening gesture to me. I think the cop made a very quick, correct decision.
wow!!brazil is hardcore, my friend was mugged when he lived there. Robbed at gunpoint in the middle of the day, gave the guy his wallet and jewelry. Guy gives him a look and new he was going to pull the trigger. Put up his hand, guy shoots him thru the hand and neck with one shot and takes off. Never caught, friend almost died and spent a month in the hospital. Funny thing is he said the worst part was when he woke up in the hospital, his wife and his girlfriend were both there(awkward!). He couldn't say anything because he had tubes down his throat.
In America of course.