Thats a good idea sir! I am holding that account and I am can basically put a sign message there. Im waiting for a miracle if he can put a sign message there.
Yeah. His silence on the accusation (though he has been online the entire time) basically convicts him. :/
If you can sign a proper message using that address, I suggest you follow these instructions to get your account back:
https://bitcointalk.org/index.php?topic=497545.0