Your neighbors don't have to know that you're the one turning them in. Document everything and if you can get pictures or a video then do! After that, you just need to turn everything over to the proper authorities, most likely Animal Control. The more you document, the more likely they are to do something about it. If it doesn't work at first, there's a whole chain of command you can go up until they get their butts in gear with it. (My father-in-law is a former Director of Animal Control). If the dog has ever bitten a person, most states have a certain bite limit per dog and if they reach that limit, they get put down without a second glance. They key is for people to report such goings on but most of the time they don't.