Keep in mind, part of officer training includes learning how to recognize behavioral signs that the person you just stopped to question over something minor is in fact worried you've stopped him for something major.
This is why they run peoples' names for warrants, run license plate numbers to see if the vehicle is stolen, etc. The initial stop may have had nothing to do with those things, but good police work is noticing nervousness and a level of combativeness/defensiveness which seems out of place given the context, and sniffing for more info.
Tell you what, those of you who think the police officer did wrong... how about now that you have a video of the deceased physically assaulting someone a mere hour earlier, you go ahead and trust the officer... who y'know, was actually there... to have had a good reason for shooting Brown?
Whatever the officer may or may not have known about Brown's strong arm robbery, he certainly knew the details of Brown's assault on his own person during the stop in question, and during the very time he shot Brown.
I consider that insight far more important in determining if shooting him was appropriate, than what someone on Huffington Post who carefully avoids exposure to "diversity" while championing it on their keyboard, has to say about it.
Or, if you prefer, continue to subscribe to the fairy tale where police officers decide to just execute black men for no reason whatsoever. Not sure why you'd want to believe that... especially since it isn't true, but knock yourself out.