The right thing to do is to first talk to the neighbor about the situation. Sadly people today spend less time talking to each other. If they are not approachable, then the next step is to speak to animal control. That is what I would do.
Call animal control that is abusive
Call Pasadena Humane Society. If I see a dog on the street or witness abuse or neglect, I always call them. There will be an option when you call to report abuse, among other things. You'll be connected to one of the employees and be able to provide the information. Thank you for being a responsible human and for caring enough to do something.
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