Tony Souza, executive director of Habitat for Humanity, Sarasota, said the Nadels were strong supporters of charities in the area. Peg Nadel has been chair of Habitat's capital campaign for the last year and a half.
"They have provided a lot of money to many of the bigger nonprofit corporations in Sarasota," Souza said. "Of course, this is a total shock to all of us. A total shock. Everyone considered them to be great philanthropists in the community. They've been around for a while.
"There are many, many black tie events and fundraisers here in Sarasota, and you would always see them very prominently there," Souza added. "They were involved right across the board."
The couple had their own nonprofit foundation, the Guy-Nadel Foundation, which gave thousands of dollars to various charities, according to its tax records.
In 2006, the most recent tax filing, the couple gave $112,000 to the Sarasota Opera, $4,000 for animal shelters, $150,000 to youth social agencies, $135,000 to a theater company and $144,800 to various churches for everything from a youth bus to general charity.
Brad Garrett, a former FBI agent and ABC News consultant, said the discussions about Madoff could have helped bring other scams to light.
"It doesn't mean there are more of them. It just means that people are talking about them more. People are coming forward. People are complaining that they lost money," Garrett said. "One of the problems is people are embarrassed sometimes that they got caught up in these things and they end up not reporting them, particularly if it's not a huge amount of money."
Garrett said such scams will exist regardless of the economy.
"Ponzi schemes attract people because they give them an outrageous percentage" return on investments, he said. "There will always be a percentage of us that will do that because there's that too-good-to-be-true thing. And we're hoping that it's too good to be true."
In the past two weeks, two other Ponzi schemes have been prosecuted by federal authorities.
Forte is alleged to have scammed $50 million out of investors in the Philadelphia area.
"Forte engaged in lies, deception and rapacious behavior at the expense of innocent investors, many of whom considered themselves his friends and close acquaintances," said Daniel M. Hawke, director of the SEC's Philadelphia regional office, in a statement. "Using other people's money, Forte promised and reported outrageous returns over more than a 10-year period, and because of his relationships with investors, was able to lull them into trusting him with their funds."
Starting in 1995, Forte allegedly reported to investors annual returns ranging from 18.52 percent to as high as 37.96 percent. But such returns were just an illusion. From January 1998 through October 2008, the trading account had roughly $3.3 million in losses.
Then just last week, Ossie of Atlanta and his company CRE Capital Corporation were charged with operating a Ponzi scheme involving more than 100 people. The scam involved about $25 million in foreign currency transactions.
Ossie allegedly promised pool participants that they would earn a 10 percent return on their money within 30 days by trading United States and Japanese currency pairs.