Source:
Raw StorySony Computer Entertainment America (SCEA) does not know who stole nearly 75 million customers' credit card numbers from their PlayStation and Sony Online services, but they claim to have a hunch.
In an open letter to members of the U.S. House Subcomittee on Commerce Manufacturing and Trade, the chairman of SCEA claimed that forensic researchers have discovered a file that was "planted" on their systems by hackers.
He told Congress the document only contained a single sentence: Titled "Anonymous," it read, "We are legion."
That is indeed an Anonymous catch-phrase, but it is not entirely clear whether this can be blamed on the group, one of its members or someone trying to make it appear as if they were involved.
Read more:
http://www.rawstory.com/rs/2011/05/05/sony-suggests-anonymous-behind-massive-playstation-attack-but-hacktivists-deny-it/