If you know the guys name and were able to Google his law firm to provide an address and phone number then call the police. He didn't borrow your laptop or forget to return it – he stole it. It's a little confusing but I'm pretty sure that you are the SB in the story and he's the SD. Do you what you would do in any other dating situation where an overnight guest rips you off and report it to the proper authorities. Since he's an attorney I would also consider reporting it to the attorney review board in his jurisdiction. I believe if you bring enough pressure to bear you will get back your laptop. I can't imagine a situation where you have more to lose than he does.