I had just crossed the street and was a witness to what happened. I did not see any mace or any other spray being used on this dog, though that may have happened earlier. I saw an elderly woman approach the dog, and heard police requesting that she keep her distance. She continued, and the dog approached her and bit her leg. I do not think that it was being hostile, but it was clearly biting her. She reacted to being bit, and the police shouted at her to move away. This is when the dog turned to the police and approached them. I can't really blame the dog, because it's a dog and it has no clue what was going to happen, At the same time, I didn't see any mace being sprayed, and I found it difficult to view this as an abuse of power when I saw it. I was very upset, and really I feel that this woman was to blame. It made no sense to approach this dog, because it was barking at people, and the cops were yelling at her to keep her distance. Within 20 seconds of the shot being fired, I heard additional sirens, so maybe animal control was on the way or something, I didn't stick around. It just makes me feel sick that this whole thing could have been avoided if the dog was given more space.