Can we mark in some sort account where the stolen bitcoins are?
You can keep tracking it on the blockchain, until it hits a mixer.
Quote
Make him do not use that money!
That's not how Bitcoin works. All transfers are final, good or bad.
I know it does not work like that! BUT MARK IT! MARK IT FOR THE HELL!
How did he steal your funds? Are you sure you have no flaws doing transactions to that address? I think you did not double check the information you give and there he got an opportunity to steal your funds. Just better luck next time.