My girlfriend wanted to sublet a room (hers) in her apartment in December for occupancy starting Jan. 1 2009. She herself is moving to Brooklyn. She found a tenant a few weeks ago and collected a half month security deposit. On the agreed move-in day, yesterday morning, he texted her to say he's sorry but his landlord offered him a discount on his rent (a dubious $600) if he'd stay, so he'd have to back out and would need his deposit back (I think he offered her $100 for "her time"). She refused, since she would now need to find a new tenant and would meanwhile have to pay the rent herself. She doesn't have a signed agreement. She emailed him a boilerplate sublet agreement that he said he would sign when he collects the keys (she has the emails, and he said he agreed). The agreement specified that one month's notice be given for moving out. I asked a lawyer friend about this, and he said it's at least an oral agreement for month to month tenancy. Then, he started threatening and harassing her. He said he would wait in his car outside her apartment until she came home to get his money. He's been calling and texting non-stop for two days and has even gotten his girlfriend to do the same. This morning, he texted to say that his girlfriend is at your apartment, please let her in (she wasn't there and has already moved out). Now he's changing his story and saying "fine whatever I'll move in or my girlfriend will move in, can I have the keys?" but, obviously, my girlfriend does not trust him and has a 20 year old roommate who is also now freaked out by all this and doesn't want him to move in. He has threatened to go to his bank and accuse her of check fraud and to go to the police and accuse her of theft or forgery or something. She has told him he's not moving in and he can find a mediator or they can take it to small claims court (the half month deposit was $650), but he seems to be ignoring this and continues to harass and threaten her (he has not threatened bodily harm). What should she do?