What Would You Do?

I met with a fellow pet-sitter this morning. She told me a story and then asked me an interesting question....She told me that on a few occasions, she heard her neighbor hitting his puppy because the dog was misbehaving. She said one time she heard the dog yelp. She was wondering what I would do if I were in her shoes. What would you all do if you heard a neighbor hitting their dog? Would you say something?