Mark has said repeatedly that Mt. Gox is under investigation and that he can't talk about it. There's a supposed IRC log from two days ago where he let it slip that he's under a gag order, saying two days ago "le gouv US ne veut pas qu'on disclose" (the US gov. doesn't want us to say anything)[0]. And he's said in public that he can't discuss the matter since he's under investigation.
So my guess is that the feds have seized his cold wallet as part of the Silk Road investigation, or even as part of the case against Mt. Gox itself, which was probably in a safety deposit box. They've already seized 5 million USD last year from Gox, why wouldn't they go after the Bitcoins, too?
And yes, the seized Bitcoins would not equal the number owed, but my guess is that they're the majority of them, say 80%.
If that's the case, account holders would have to petition the USD to prove they're not drug dealers and or tax evaders to get their money back.
I find it extremely unlikely that MtGox would falsely claim that they suffered a theft due to transaction malleability (a real point of possible error) if the actual issue was a US Government seizure. It just strikes me as utterly unbelievable that they would actively cover up (rather than simply failing to disclose) a government seizure.
It's far, far more likely that Karpales is either grossly incompetent or a thief than it is that he's making up complicated stories to cover up a government action.
You can't disclose if you are under a gag order. If Mark was running a fractional reserve because the coins were seized, and they got hit with the transaction mailability issue, that could set the stage for what we're seeing today.
I agree Occam's Razor applies here. That said, we still don't know a lot about what happened.
I like that. "Prove you're not a drug dealer and we'll see if there's still money to return." It kind of gives the middle fingers to 3 somewhat-important US rights: the right to not self-incriminate (being coerced into providing new evidence that might be used against you), being considered innocent until proven guilty (assets seized without an active case against you), and that everyone is equal under the law (unless we say you're a drug dealer (or, going back 60 years, black)).
"There's a supposed IRC log from two days ago where he let it slip that he's under a gag order"
It isn't supposed you can go read the IRC transcript. He said no such thing. What did happen is, in response to the question of what would he like to tell everyone who is waiting for news he replied with a link to a image with a Batman quote about failure. The image happened to be hosted on an image sharing site called 9gag.com. People think that was his secret way of signaling that since the word "gag" was in the website's URL. It is a total ridiculous conspiracy theory to think that he is under some kind of gag order that is preventing him from telling the truth about what happened to the coins.
It wouldn't even have to be a judicial order. The FBI or Treasury Department agent could just tell him something like "keep quiet about this or you're looking at 10 years in a federal prison". This is how prosecutors work here in the U.S., and Mark is under investigation by the U.S. government.
I don't believe this is right, but this is the reality.
Why is it so unlikely that they seized more money, probably in the form of paper wallets from a safety deposit box? Japan law enforcement works closely with the U.S.
But here's what they really wanted from Mark, and I wonder if they got them: all the Mt. Gox account records, including IP logs and bank account numbers.
You can't really seize bitcoin. you can think you have. The only thing you need is a private key so if you store this in a encrypted file like you can with wallet.dat you can seize this file.
mean while you can have already split your key into parts and give them to trusted people. setup a dead man switch to email those people to talk and recombine private key, import into wallet and withdrawal funds.
this would have worked beautiful in silkroads case because the private was encrypted.
Feds sized silk road and the Bitcoin wallets
If any was stored or transacted at MTGox this might be some of the amount of losses MTGOX is now showing but NOT ALL OF The lOSSeS obviously