Why don't you print out all the threats and call somebody for help?If this person knows your adress it's someone close to you. Might be one of your friends. Take the print outs and show it to all your firends, somebody is gona say something if they recognize it.Maybe another friend is in the same situation. If somebody else received the same emails don't hesitate to go to the police before somnething more serious happens.Don't take my advice lightly,bad things happened to me because I trusted close friends and never believed there are crazy people on the internet.I was wrong!!!!