Even if you get his address he might not keep it at home. I know how these people work. They steal a van (sprinter) and they steal as many bikes as they can overnight, and in the morning that van full of bikes is not in the country anymore, so I hope you are not dealing with these guys. Get his address, go there and tell him you got a tracker on the bike or something, and if he gives it back you will not tell anyone ( but you will when you get your bike back) or something like this. You tell him you know he did it, I'm sure you will think of something, honestly me if I could catch bastards that stole my wheels and kick my car (focus) I would just break there necks in half... I know how it feels, and sorry, hope you can find them and do your own justice.