There are better ways than ASSUMING you KNOW better and can judge others and their SITUATIONS without any bias or hate. Police, CPS, Animal Control... there are a hell of a lot of better options out there for any situation that you present. Who are you to take situations you don't know 100% about in your hands? You are no one. Honestly, I am no one. I can get people who know how to handle things I can't. That fucking simple. If a dude is beating up a chick? I'm gonna call the cops and restain him, not beat him up, that fucking proves nothing and I'd be arrested for assault too.
stealing is stealing bro, plain and simple. you nor me, is of any right to take things away from another human being, your attitude on that is just ignorant and one day you will learn.
Well, there is google, you could do some research to back up your claim no? but again you're proving just to be ignorant on the situation now.
To answer you question; I'd call Animal Control and the police. I'll let them handle it and know I did the right thing.