lving in fear of violent neighbor

I have been living in the same apartment for 28 years. Recently my landlord’s nephew and his wife took over the property and live above me. The wife is constantly screaming, swearing and complaining. Oddly enough ,she complains about noise  in the neighborhood, but it used to be quiet until she moved in. She says My car is too loud, music is too loud ,dog is too loud,etc.,etc.,etc. She gets her husband agitated and he has become agressive towards me. Recently he greeted me as I came home from work by throwing things swearing and yelling at me and saying He is going to evict me. His eyes were crazy and i thought he was going to hit me. I am constantly afraid that he is going to physically harm me or do damage to my nproperty. The real issue is the wife wants her sister to move into my apartment.(The walls are paper thin, I hear everything they say.) I there anyting I can do to protect myself until I can move? They haven"t sent me an eviction notice yet. Don’t they have to put it in wrinting or was his threatening me a legal verbal notice? Help me before he kills me.