As it stands she may be pissed off at me but I have not contacted the police as I said I would not.
That is about as a misconstrued sense of honour as I have ever encountered. Sorry. You have zero moral obligation to hold up any such bargain.
I suppose you feel that the deterrant threat of being exposed is less protection than the police would provide?
You posted her name. If she was involved she will now be extra-pisssed. If she wasn't involved, now she will be pissed. There are some simple steps you can take to protect yourself. One of which involves calling the police.
Anyway, your business. WTV dude. You don't seem to want to, so so be it. I sure hope she wasn't involved, because if she pulls this stunt next time, with another unsuspecting mark, and it goes bad and the mark is hurt, you will be in part responsible. I hope at that point you will man up and testify.
Sorry to be so blunt dude, I know you went through a terrible situation and it can be confusing, but you do have to consider potential future victims, too. If Brandy and her boyfriend wre not involved, they should be showing concern, and a willingness, indeed a desire to clear their respective names, so that the real perpetrator can be sought and caught.