"Since they are seldom burdened by guilt or shame relateing to their illegal maneuvers, they often continue bilking innocents until they're caught," said Friedman.
Keele Maynor's attorney, however, said his client's remorse is genuine.
"She's very interested in paying the people back," said Stuart Brown, her attorney.
Unfortunately, legitimate charities are hurt by the type of fraud allegedly perpetrated by Kirilow, Leone and Maynor. Stories about scams make it harder for them to raise money, because people tend to lump all charitable causes together, said Jill O'Donnell-Tormey, executive director of the Cancer Research Institute.
"People think we are all the same thing, and all these organizations are suspect," said O'Donnell-Tormey.
Some experts believe that many people who perpetrate scams are mentally ill.
"They're not necessarily psychopaths, but it's the kind of behavior that tends to attract psychopaths," said Robbins. "There are also some people who believe they have cancer but really don't. They may be hypochondriacs or suffer from delusions, but that's a lot less common."
"Some may say that greed and selfishness are psychological disturbances," said Michael Lewis, university distinguished professor of pediatrics and psychiatry at Robert Wood Johnson Medical School in New Brunswick, N.J.
Robbins is skeptical that fraudsters carry out their schemes due to sheer desperation.
"People who are desperate are easier to detect. As you start to talk to them, they don't look like they're telling the truth."
Because these con artists are so skillfully manipulative, experts said it's easy for people to fall victim to their claims of a serious illness and want to help.
"If they are true psychopaths, they're good at fooling people," said Robbins. "You won't notice any signs that they're nervous."
"Most of the time, people believe you're telling the truth, which is why they can get away with it," said Robert Mitchell, foundation professor of psychology at Eastern Kentucky University.
Since Kirilow, Leone and Maynor all carried out their alleged frauds via Facebook or on blogs, their deception was all the more difficult to detect.
"It's easier to spin the story online, because there are fewer signs that their story is implausible," said Mitchell.
Even though the victims of these crimes don't suffer physical injuries, experts said these crimes are particularly heinous because of their emotional toll.
"It leaves people feeling betrayed and questioning whether they should be so kind," said Robbins. "They not only feel angry at the person but angry at themselves."
"How can we survive if we have to be suspicious of everyone," said Mitchell.