The married owners of a group home for the mentally ill were convicted Monday of enslaving its residents, forcing them to work naked and perform sex acts, and illegally billing their families and the federal government for therapy.

Arlan Kaufman, 69, and his wife, Linda, 62, were convicted of 30 federal charges, including health care fraud, Medicare fraud, forced labor and holding clients in involuntary servitude at the Kaufman House Residential Treatment Center.

The convictions could put them in prison for the rest of their lives. Federal prosecutors contended the Kaufmans controlled the lives of the mentally ill residents, including forcing them to work on their farm and deciding who could wear clothes.

The couple was accused of forcing residents to masturbate, fondle each other and shave each other's genitals — activities Arlan Kaufman videotaped.

The Kaufmans claimed that nude therapy sessions and other treatment methods had therapeutic value for schizophrenic patients, and that having residents act out problem behavior helped them avoid repeating it. Arlan Kaufman insisted that the residents' behavior was voluntary.

Prosecutors called it abuse and said it spanned more than 20 years while the couple billed Medicare more than $216,000. The Kaufmans incorporated their unlicensed treatment center in 1980 and ran it until their arrests in October 2004.

Justice Department lawyer Kristy Parker told jurors the residents were turned into "uncompensated actors in a never-ending pornographic movie."

The defense had portrayed the couple as respected professionals who were married 40 years and raised three children of their own.

"It was therapy. No one was harmed. They were helped," Arlan Kaufman's attorney, Tom Haney, told jurors.

Linda Kaufman's attorney, Steve Joseph, argued prosecutors had no solid evidence against her. He noted that in one videotaped session, she was reading a newspaper and didn't even look at the nude resident.

The Kaufmans face up to 20 years in prison for each of the conspiracy, forced labor and involuntary servitude charges; up to 10 years for each health care fraud charges; and up to five years for each of the other charges. No sentencing date has been set.