Federal prosecutors have alleged that Leimer reaped millions installing internet phone lines in the illegal call centers -- a charge he denied when ABC News found him in a posh gated community in Costa Rica.
"I have had nothing to do with it," Leimer said. "I've never had anything to do with it."
U.S. Postal Inspector Jose R. Gonzalez told ABC News Leimer was "lying."
"He's currently under indictment, and there is sufficient information and sufficient evidence for us to be able to not only indict him, but also, I feel, definitely put him away," Gonzalez said.
Federal officials thought they had extinguished the scam in 2006 when they conducted a dramatic raid on 16 boiler rooms in the Costa Rican capital of San Jose. Stephen W. DeWitt, a special agent for the U.S. Diplomatic Security Service, said the Costa Ricans sent more than 150 agents into the call centers in a complex operation that needed sanction from top Costa Rican judges and law enforcement officials. "Everybody acted in concert," he said.
Peter B. Loewenberg and Patrick M. Donley of the U.S. Justice Department's criminal fraud section helped put 37 participants behind bars. Two of the masterminds of the scheme received 50-year sentences.
But U.S. authorities have marveled at the scale of the scam that has regenerated – believed to be the product of the Costa Rican citizens who remained free after the 2006 raid. And they say the potency of the swindle remains breathtaking . One early victim in Florida wired more than $800,000 to Costa Rica on the promise of a million-dollar sweepstakes check that would never arrive.
"Any time you have a scam that earns a lot of money, you know it's going to pop back up," said Anthony V. Mangione, the special agent in charge of Homeland Security investigations in Miami.
Mangione said some of the callers have pretended to be Customs agents, "taking our good name and eroding public confidence."
The scams have also been personal for Federal Trade Commission Chairman Jon Leibowitz, who told ABC News his own mother was called by the swindlers. "She calls me and goes, 'Jon, I won this sweepstakes, and I'm just wondering if it's possible that this could be not legitimate.' And I was like, 'Mom, I think it probably is a scam.'"
But among those most alarmed have been the officials who lead the Make-A-Wish Foundation, which relies on the trust of the public for its funding. Earlier this year, the non profit organization posted a fraud alert on its website. But Allvin said the volume of calls from victims only increased.
"We've never seen something so despicable," Allvin said. "These people around hiding offshore -- willingly destroying people's lives by taking every nickel they can suck out of them. And they're using the good name of the Make-A-Wish Foundation to do it. I'm not sure how much more you can pile on top of that collection of underhanded tactics just to line your own pockets."