Actions and how you account for them are what make a man. You don't automatically start with respect; you earn respect by being moral and kind and doing the next best right thing. You then continue to follow a path which allows you to keep the respect you've established.
An officer of peace and law should be respected. He should also respect. He should practice some magnitude of fairness and have assessed a situation completely before impulse action is taken. He should be kind unless he is in immediate danger and without a way to retreat.
Any moral human being would know that multiple shots is in excess to kill even a charging bear, much less a family pet. This seems especially true when it involves a bound up family pet that may or may not be doing what he felt was his duty, which was to protect his people and property.
I don't know, is what I have to say to you naysayers, how this officer's actions can be justified. If this was truly some sort of self-defense, the officer's actions could have been prevented by considerate actions on his part. He could have called Animal Control intervention at the first sign of threat. He could have called for back up. He could have walked away.
He could have made a statement by now.
The dog may have been just a dog to some of you. My girls are not just dogs to me. They've been a blessing to me and are a major component of my family. I value them over most and choose to be around them as humans fail to be, well what you'd expect to be, of humans.
If someone did what the officer allegedly did was drowning along side one of my girls and I had the chance to save just one - I'd be sure to tell his family that he waded well for a while...