According to by the U.S. Federal Bureau of Investigation's Internet Crime Complaint Center (IC3), victims reported total losses of US$559.7 million in 2009, more than double the tally for 2008.

The most frequently reported scam was one that used the FBI's own name to try and trick victims into handing over cash or sensitive information. One such scam involved an e-mail claiming to be from FBI Deputy Director John Pistole. Here the scammers tried to trick people into paying bogus fees in order to receive an even larger sum of money, a payout that never arrives.

FBI -themed scams accounted for 16.6 percent of the 336,655 complaints that the IC3 received last year.

Total complaints for 2009 were up 22.3 percent from the previous year, when victims posted 257,284 complaints and registered $265 million in losses.

Other common scams involved the non-delivery of merchandise or payments -- a common form of fraud on online marketplaces such as eBay -- advance-fee fraud similar to the John Pistole scam, and identity theft. Fake antivirus software was also common in 2009, the FBI said.