If you are having issues with your next door neighbor where you are afraid of him, you need to immediately speak with your landlord about the situation and follow up with that conversation with a written letter memorializing the conversation with a plan as to how to remedy the situation.If the landlord does not intervene, you should contact a landlord tenant attorney about ways to resolve the problem such as filing a petition for a restraining order against the neighbor or even filing a police report. If the conditions become too intolerable, you might need to end your lease with your landlord for the premises.