From what is visible on this video, this cop was 100% wrong shooting this guy in the back as he attempted to run away. If the video depicts the entire scenario accurately, the cops was in no danger when he shot the man. What happened before, I do not know.
How unfortunate these situations are. If it is even possible, (I have my doubts) it is going to take a monumental effort by the entire country to turn around the racial strife in the country because of incidents like this.