i would suggest introduce yourself to your new neighbor and meet their dog. that way you know the people you can voice your concerns and see just how responsible they are with their dog and you will know the temperment of their dog. DO NOT bring Quinn when you meet them. It is quite common in this breed for them to be dog aggressive no matter how they were raised or socialized. i would not call animal control on the dog because of what has happend so far it is not dangerous because of the incidents. i know that if someone called on me because they feared my dog and had not even met him i would be pretty upset. the best thing you can do is talk to your neighbors make sure they are responsible and keep him on leash and properly contained at their property and also keep your dog on leash when outside so that there is no chance of them ever meeting. dog aggression in this breed is common and can be managed with proper training. i do have to say i think it was great that you decided to come here and research and get to know the breed more before making your full judgement. there are a lot of responsible pit bull owners out there