Why won't you reply to his lawyer? I don't blame him for not wanting to send you his docs, you guys had him balling around for months. Who's to say you won't do it again? Fact of the matter is you should give him back the money you owe. From your replies I can see the issue is that you want his notarized documents, not that the BTC are stolen as you claimed in the chats. Seems to me like you are just formulating new excuses. I'm sorry but I've been called out so much on this forum, now that there is actually a scammer I'm happy to ham down.

EDIT: I wonder if you used his BTC to buy VIP... shame.