More weird emails, and regular mail

I got a note in the mail today; it was creepy as fuck. I'll post a picture up when I get the chance. Yahoo also managed to displease me; I blocked the guy who sent the message from my last post, and he managed to send another: Poor little naive boy, you cannot begin to understand my existence or my prescence while you write on your silly blog. (Name removed) is dead now, you see my symbol on your walls, right? You're next, prepare yourself. Someone tell me who this is before I kill someone from insanity.