How is it possible we still don't know where that insane amount of coins went. Crazy.
"Government gag order" is a convenient excuse; wasn't it used in another scam before? But if the coins had been seized, there should have been charges pressed and arrests by now, as in the SilkRoad case.
If the coins had been stolen by hackers, Mark should have provided details and asked the community for help to track him down. If he had lost the coins, he should have publicized the address so that everybody could check that the coins were not moving anymore.
Another possibility is that it was an inside job, perhaps an attempt to trade with client coins that collapsed. In this case, there must have been several other people involved. People with far more money than respect for the law. Talking may be dangerous, one may get this sudden urge to jump from a tall building when there are no witnesses around.