If video is ever available in these situations, they should always be made public. You can see the short, 24 second video of what transpires here (nothing graphic).
A Forth Worth police officer pulled over a truck that had people illegally riding in the bed. As the truck pulls into a driveway, you see a dog come out of the front yard and happily greet the teenagers jumping out of the truck.
Unfortunately, the police officer makes a very big error when approaching the kids. I don't know if he's yelling or talking loud, but he's waving his arms, gesticulating wildly. The dog reacts by trotting over and barking. He does not appear overly aggressive (i.e. trying to bite), but is warning the officer in clear and simple terms. The officer backs up and, even though there are two teenagers mere feet away (one who could have easily been asked to grab the dog), draws his service weapon and shoots the dog twice. The video does not show the actual shooting of the dog - it occurs slightly off camera and below the dashboard.
You do see the kids react to the fact that, hey, there are now bullet fragments in their bodies and their dog is lying, gasping for air on the ground. One teenager has bullet fragments embedded into his leg, the other received a graze wound. The dog is alive.
Yes, officers should defend themselves. Yes, sometimes lethal force is necessary.
But I think the video highlights some gross misunderstanding of dog behavior and a rather heavy-handed response to a dog barking. Since police officers do encounter dogs on a semi- to completely regular basis, helping them learn to diffuse situations involving barking or outright aggressive dogs without using lethal force FIRST...well, that seems like a good idea.