The thug wakes up soon enough, still groggy from the concussion you must have given him. It looks like he doesn't remember that you're the one who just knocked him out. Perfect for giving you choices.
Before he remembers what you did, have him turn himself in. Then, even if he gets his memory back, it'll be too late. Get him to take you to wherever he's operating from and hope he doesn't go back on you on the way there. Ask him what he knows before he remembers what you did.