Victims of fraud perpetrated by a family member are more likely to have modest incomes. Such were the relatives of master fraudster John Ruffo. As reported by CNBC's "American Greed: The Fugitives," even after Ruffo got caught defrauding seven banks out of $350 million, he wasn't finished breaking hearts. Next, he turned to his relatives.
"He was really good at keeping secrets," Ruffo's ex-wife, Linda Lausten, told "American Greed." When bail was set at $10 million, Lausten, his elderly mother and five of his aging aunts and uncles put up their homes as collateral. "There are all these little people, elderly people, so innocent and naïve," said Lausten. "And we just signed away everything."
(Read more: Mortgage fraud: What you need to know)
Two years later, Ruffo, convicted and sentenced to 17 years in federal prison for the biggest bank fraud of the decade, failed to surrender to serve his sentence. He ran—knowing his wife, mother and relatives would all forfeit their homes. His mother died in a nursing home; she never saw him again.
Even Ruffo's attorney couldn't believe the extent of Ruffo's treachery. "To this day," Judd Burstein told "American Greed," "it astounds me that somebody would do something like that and that to me is really pure evil."
"It was a very selfish act," Deputy U.S. Marshal John Noel told CNBC. Ruffo is still a fugitive, and Noel, the case agent, is still searching for him. "I wish I could give it 110 percent of my time."
For anybody who cares about investing, protecting yourself from skillful hucksters can be tough. "Fraudsters who are 'good' at their game will put you into a heightened emotional state," said Walsh. They talk excitedly and create a feeling of pressure. "They aim to move you from the rational side of your brain to the emotional side."
Slow down, advises Walsh. "Don't make snap decisions. Ask questions to take charge of the conversation." And above all, said Walsh, stay rational.
—By Celia Watson Seupel, Special to CNBC
CNBC follows the money trail in search of the most wanted white-collar fugitives."American Greed: The Fugitives" airs Thursdays at 10 p.m. EDT.