Because the landlord did not create this situation, there isn't really anything that he or she is required to do. They can certainly let you out of the lease agreement if they so choose; however, they have no obligation to do so. You could contact the police or file a Complaint to obtain a protective order against your neighbor.
The information provided herein is general information only and not legal advice. The information provided herein does not create an attorney client relationship and is not a substitute for having a consultation with an attorney. It is important to have a consultation with an attorney as the information provided in this forum is limited and cannot possibly cover all potential issues in a given situation