Most of the blame has to go to the owner. Suspect is right, if you want an educated opinion on this, you need to watch the second video (you don't see the dog getting shot in this one). The guy pulls up and stops in the middle of the street, proceeds to turn his music up even louder, pulls up to the curb, gets his big ass dog out, and stands on the corner with his chest puffed out. He knew what the he was doing. He's also a dumbass for not being able to control his dog. When the police were approaching him he should have calmly said, "let me put up my dog, it has the potential to be aggressive because, you know, it is a rottweiler and all". Secondly, he should have rowed his window up. Thirdly, he should have called to his dog as it approached, he ed up countless times.
That being said, the police man who shot the dog needs his ass kicked. Trigger-happy Mikey needs his gun taken away. What in the was he thinking? Repeatedly shooting the dog and just letting it suffer proves that he is a head. Also, reaching out to the rottweiler helped to provoke it. R.I.P. Rottie