Agents at the U.S. Secret Service office in Orlando, Fla., believe a Problem Solvers investigation has uncovered a new, more sophisticated variation of the so-called "Nigerian 419 Advance Fee" scam targeting Americans who sell items over the Internet, according to Local 6 News.

The variation of the "Nigerian" scam involves authentic-looking cashier's checks that are issued for high-priced items.

"We are talking about very sophisticated criminals," bank security expert Laz Claro said. "These people are very well educated, these people know our system. "They know our economy and they know the different types of financial instruments that can be purchased."

Local 6 News reporter Mike Holfeld asked, "Are we looking at a new look at an international sting that could victimize Americans across the country?"

"No doubt about it," an agent said. "Anybody using the Internet, anywhere needs to be cautious."

Local 6 News featured a recent victim of the "Nigerian" scam, Palm Bay, Fla., resident Wil Andrews.

Just weeks after the 28-year-old man posted a 1979 classic truck online, an international broker sent Andrews an e-mail that said his company had a client who was interested in purchasing the truck for the asking price of $3,900.

"It sounded legitimate," Andrews said. "But I wasn't really buying it until the check showed up."

A cashier's check from the Arizona Federal financial institute was delivered to Andrews' home shortly after the e-mail.

Local 6 News reported that the check was "the hook in an international con game sweeping U.S. bank accounts."

The cashiers check was written for $7,000, which was $3,100 more than the original asking price.

Holfeld asked," What was the additional money in the check supposed to be for?"

"Finders fee and shipping costs," Andrews said.

Holfeld reported that "that's the deception. The checks are counterfeit. By the time you wire the shipping fee your money and the cyber thieves are disappear."

Andrew's bank, Riverside National Bank, caught the counterfeit check on the spot and the organization's security team has been on alert after four of its customers have recently lost thousands written against what appeared to be valid certified checks, Holfeld reported.

Local 6 News reported that the investigation has uncovered a pattern of counterfeit checks delivered to customers of major banks dating back at least 14 months.

Holfeld reported that "it appears the global operation is escalating in scope."

The investigation will continue Tuesday night at 11 p.m., when a major Florida bank goes public with their counterfeit check victims that total millions of dollars, according to Local 6 News.