First off, the "robbing a convenience store is 1) not correct,as it was not a robbery; 2) irrelevant to the altercation with Wilson and 3) not a crime that gives rise to a death sentence. This item is completely moot and did not give rise to his death.
Second, you have no basis to decide if it is all his fault as you do not know what went on, unless of course you are witness #10. The fact that an unarmed man was killed by a cop should beg the question amongst reasonable thinkers as to whether his death was necessary. Of course, that would something reasonable thinkers. I appreciate the fact that they are many that just don't think too deeply.