If he took the BTC he can simply give them back to us, if somebody else stole them, he could deliver enough information to be able to track the blockchain and verify this information.
Right, He went to the trouble of orchestrating his heist of USD and
BTC just to give them all back.
He knew what he was going to do before he started Mt.Gox. From the GetGo he planned to rob people.
On another thread here, there is all kinds of evidence that Mark is a long time scam artist.