If the guy really is about to commit a crime - and you know about it, you have to tell - remember how you felt when he ripped you off? People have to learn that this behaviour will not be tolerated.... it is bullying to the nth degree. It doesn't matter if he says he loves you. I had my skull fractured, and a fair bit of internal damage done by someone who said he loved me.Good luck, and I'll be thinking of you.
Don't forget, you can always report a crime anonymously to the Crimestoppers line.... they will listen, and you are guaranteed no names.