Only the media and Michael Browns friend who was a witness made it sound like the officer EXECUTED brown until the witness was proven to be lying and the media was forced by the evidence to report facts which they hate when it doesn't support the sensational story they want to tell to keep people watching.
As far as your comparison of white collar criminals vs stealing a car, take a look a the difference, HINT skin color isn't the important difference. MONEY is the difference. When you can afford $500+/hour lawyers, you can buy your way out of trouble. OJ, Adrian Peterson, Ray Rice, etc...... Those aren't white collar criminals, but everyone knows they are guilty of the crimes they are accused of, money is why they aren't in jail.