that's only half the truth, here's the story of the so called "fraudster": http://forum.bitcoin.org/index.php?topic=20207.0
Kevin/toasty admitted to be the buyer, but he is not the hacker (at least, he claims he isn't and Mt Gox seems to agree). The article suggests that these two parties were either the same person or were at least in collusion, but there is no proof of that whatsoever.
There is no independent proof of Mt.Gox's claim either is there?
Compared to an official line from a company or government, it's pretty shaky.