"A two-year undercover FBI sting operation targeting online 'carder' forums hosted on the DarkMarket.ws Web site has netted 56 arrests and prevented about $70 million in fraud losses, the FBI said Thursday. DarkMarket.ws was widely used by online scammers to buy and sell stolen credit card numbers, other financial information, and even the devices used to make fake banking cards. Before it was shut down earlier this month, the Web site had registered more than 2,500 members. Although Dark Market was thought to have been administered by a criminal going by the name Master Splyntr, German Public Radio reported on Monday that the FBI had been running a sting operation on the site since late 2006, and that Master Splyntr was actually an FBI agent named J. Keith Mularski."