The Verge reports that "Tokyo-based Bitcoin exchange Mt. Gox lost $400 million worth of bitcoins in February. Its management said the amount was stolen after hackers exploited a transaction bug to divert the funds, but some of Mt. Gox's users are not so sure, suggesting instead that the exchange's owners pocketed the cash. Now, facing silence from those owners about the fate of the money and the methods by which 6 percent of all of the Bitcoin in the world could have been stolen, a group of hackers claims it has broken into the bankrupted Bitcoin exchange's network to get answers. ... Forbes reports that the group gained access to the personal blog and Reddit account of Mark Karpeles, Mt. Gox's CEO. The hackers used the platforms to post a message that claimed Karpeles still had access to some of the bitcoins that he'd reported stolen. In support of the claim, they uploaded a series of files that included a spreadsheet of more than a million trades, Karpeles' home addresses, and a screenshot purportedly confirming the hackers' access to the data."
(The Forbes article
on which the Verge report is based.)