This happened a few miles form here and they've been showing the video on the news a lot. (By the way, it was a Cookeville police officer that shot the dog, not a State Trooper).
I actually think it was a pretty tough call on the officer's part. First, the dog was hardly a "tiny little thing", I'd say 50-60 pounds. And the dog was running at him at the time. Whether or not he was "playing with the flashlight" is speculative, but I doubt it. In retrospect, the dog was obviously scared and excited, but in the few seconds the officer had to make the decision I have a hard time second-guessing him. Finally, the Police Chief and mayor have met with the family and profusely apologized.