Don't know where to put this but need advice

my roommates family has been harrassing her since she moved out and we have reported it to police but now her aunt has apparently some how gotten my roommates car sign over into her name through the bank. her aunt was the cosigner but my roommate is the only one on the registration and has not sign over anything or got notified her ownership of the car has been terminated. so her aunt is saying that if she doesn't give them the car that they'll call the cops and report it as stolen. can they legally have changed the ownership of the car without her knowledge or consent? (they're harrassing her for moving out and getting engaged to my brother in law who they don't like for his race but that's another story). either way is any of that legal? how can we fight this if the cops do show up? somehow her family found out that she was living with me and found my house when no one ever gave them my address and they've been watching my house. we have the car parked somewhere else and I pick her up and sneak her in the house now so they don't see her because they have threatened bodily harm to her. she has voicemails of all threats as well but police haven't helped much.