In , the U.S. Federal Bureau of Investigation describes the complex path its investigation has taken as it has searched for the computers that served as a central meeting point for the attacks.

After Germany's Federal Criminal Police raided service provider Host Europe, they linked one of he IRC servers to Dallas's Tailor Made Services, the documents state. Two hard drives were seized from Dallas's Tailor Made Services on Dec. 16, the Smoking Gun reports. Another IRC server has been traced to Fremont, California's Hurricane Electric.

Neither Hurricane Electric nor Tailor Made Services could be reached immediately for comment Thursday.

The early-December attacks were part of a grassroots campaign called "Operation Payback," which tried to put pressure on companies that had severed relations with WikiLeaks after it began publishing classified U.S. Department of State cables. Operation Payback is the work of a group called Anonymous, which has launched similar attacks against the Church of Scientology and the Motion Picture Association of America in the past.

The attacks were strong, but minimally disruptive. They knocked Web sites offline, but they didn't touch any of the target's back-end transaction processing systems. They also garnered a lot of publicity for Anonymous.