Four people have been convicted in a hacking conspiracy that apparently targeted PayPal Inc. [ a subsidiary of eBay Inc (NASDAQ:EBAY) ], Visa Inc (NYSE:V), and MasterCard Inc. (NYSE:MA).

anonymous hackers group

Bloomberg reports that all four of the hackers who were convicted are members of Anonymous, an online group some have labeled a “hacktivist collective.” Today, a jury found Christopher Weatherhead, whose Internet handle was Nerdo, guilty of conspiring to attack the websites of various financial services companies. Attorney Russell Tyner called Weatherhead a “cyber-criminal, who waged a sophisticated and orchestrated campaign of online attacks.”

Peter Gibson, Ashley Rhodes, and Jake Birchall were his co-defendants in the case, and they pled guilty to the charges at an earlier date in London. According to prosecutors, the hackers targeted the companies because they decided to stop handling payments for WikiLeaks after it published massive amounts of classified documents two years ago.

Prosecutors in the UK said in 2010 the group targeted various websites and purposely caused them to crash by inundating them with messages and requests. The group referred to the attacks as “Operation Payback.” SkyNews reports that when an Internet user attempted to go to one of the sites that was being attacked, they would then be redirected to a page that read, “You’ve tried to bite the Anonymous hand. You angered the hive and now you are being stung.”

In addition to the financial services websites already mentioned, the four were convicted of targeting the International Federation of the Phonographic Industry, the Ministry of Sound, and the British Recorded Music Industry. Prosecutors believe the group targeted those websites because of their anti-piracy stances.

Prosecutors said the group’s attacks resulted in costs of $5.6 million in sales losses and other losses like the purchase of additional software and payment for additional staffing.