Police say Alicia and Steven Kelly won the sympathy and financial donations of friends and strangers, telling them their 15-year-old daughter suffered from bone cancer.
But the person they exploited the most was their own teenager, convincing her that she had a deadly disease by giving her blood pressure pills and telling her it was her "chemo medicine," according to police in Greenwood County, S.C.
And that wasn't all, they say.
The couple, who were responsible for looking after her elderly father, allegedly neglected his care, leaving him to die in a trailer while they collected his Social Security checks for 18 months, allege police.
The Kellys -- 38 and 39 years old respectively -- spent the last two years lying to their community and their children, saying they did not have enough money to treat their daughter's disease, said police.
Efforts by ABC News to reach the Kelly family were unsuccessful.
"They were doing two scams at the same time," said Major John Murray of the Greenwood Sheriff's office. "There is not much difference than somebody going out and robbing somebody with a gun. What they did was instead of using a gun to rob people, they used sympathy to rob people. It's the same difference. One plays off of fear and one plays off of sympathy."
"A few months into it, the daughter figured out she didn't have cancer," according to Murray, who said police were eventually tipped off and arrested the couple on five fraudulent check warrants on Feb. 4.
"The girl's parents had gone to churches and different community groups to raise money, including the American Cancer Society's Relay for Life, according to Murray.
Joining the website Caring Bridge to gain sympathy and donations, the family chronicled their daughter's bogus illness with "58 pages written on how sick she was," he said. There are four other children in the family, aged 13, 12, 3 and 2.
"It's a tragedy, especially for the children," said Murray. "This is something they will have to deal with for the rest of their lives."
Psychologists and child development experts agree that exploiting a child who has a parents' ultimate trust can have devastating consequences, including depression or suicide if she is not emotionally stable enough to weather the storm.
"We can be looking at serious post-traumatic stress," said Anthony Siracusa, a clinical psychologist from Williamstown, Mass., who specializes in families and child abuse. He has not treated the Kellys' daughter.
"A diagnosis of cancer, as we can all imagine, is earth-shattering," he said. "To think your life and longevity has been questioned."
Siracusa said the girl might also develop a fear medical treatment. "Even if she is cognitively wise enough, she may not be emotionally."
"It could have an impact on how she cares for herself in the future, or the ability to care for children as a parent," he said. "She may have some real serious problems."
Siracusa said authorities should ensure that the teen gets support, not only from relatives, but from professional counseling.
Police said that the girl, whom they would not identify because she was a minor, is now living in Greenwood with her paternal grandparents and her other siblings.
Social services is providing financial support, food and counseling for the family, they said.