I know the video and seeing how he was about to hit his partner with his bat/crowbar (whatever he had in his hands), I think it was justified. A hit in the head with a crowbar can quickly be lethal. Wether shooting him while he was already falling him was correct, could be doubted, but generally if cops in the US shoot, it's to kill; other than that, he might have just had the adrenaline rush or shock of the guy turning around, which might have caused him to shoot multiple rounds at the guy, even when he was already collapsing.
In my opinion, the cop did the right thing, after a taser had failed, releasing a dog wouldn't probably done much effect, other than the dog getting hit with that crowbar and possibly dying.
After watching this "brown townysis" video, I'm mad at the creator. He isn't much better than the people filming it. It's just yet another sensationist commenting on the "mistakes" the policemen make, while trying to protect their community and lives. In such a situation, which is a lot of stress and mental tension you can't expect them to do everything right. To be honest, I'm glad no officer, wether K-9 or human got hurt and the agressor was put down. It's unfortunate that he died, yet it's, in a sort of way, his own fault.
