The Missouri attorney general on Thursday sued the owner and operator of a group home where 10 people died in a fire, claiming the business had been secretly and illegally run by a man previously convicted in a Medicare and Medicaid fraud scheme.

The lawsuit seeks to recoup $689,491 in Medicaid payments made to Joplin River of Life Ministries Inc., plus damages of about $2.1 million and an unspecified civil penalty for each allegedly fraudulent Medicaid billing made by the company.

A Nov. 27 fire at the business' Anderson Guest House in southwest Missouri killed 10 people and injured two dozen. Investigators have not pinpointed an exact cause but have said improper wiring in an attic may have been to blame.

"Oh boy, I just can't believe it," Robert DuPont said Thursday evening upon learning of the lawsuit through a telephone interview with The Associated Press.

DuPont contends state inspectors knew he was involved in the business. He called assertions he had concealed his role "ridiculous" but said his work never involved the actual provision or administration of care to residents covered by the Medicaid health care program for the poor.

Attorney General Jay Nixon alleges that River of Life Ministries — which also operates three other group homes for the mentally ill and disabled — lied to state regulators to conceal that it was run by DuPont, who was sentenced to federal prison in 2003 after pleading guilty in a fraud scheme.

DuPont was barred by state law from operating a long-term care facility and prohibited under federal law from participating in the Medicaid program.

Although none of the business' state licensing applications listed DuPont as the operator after his convictions, DuPont acknowledged in an interview last week with The Associated Press that he had continued to be paid to assist his wife, LaVerne DuPont, in River of Life Ministries' operations.

The lawsuit claims Robert DuPont controlled the company's management, finances and decision making — even overriding the board of directors if he did not agree with it. DuPont "was the brains behind the operation," the lawsuit claims.

Documents obtained by The Associated Press under Missouri's open records law revealed a history of fire safety violations and violent incidents at the Anderson facility and others owned by the same company.

Officials at the state health and mental health departments acknowledged Wednesday that inspectors who encountered DuPont on the job likely did not realize he was blacklisted, and their notes were not shared with state licensing officials.

"Everybody in the world knew what I was doing and I didn't understand it any different," DuPont said Thursday. "Then a fire happens and all of a sudden they're unaware of what I was doing."

An employee reached by telephone at Joplin River of Life Ministries said no one was available there Thursday to comment on the lawsuit.