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A man stole a physician's identity and pretended to be a doctor for a year in South Carolina, and now investigators are combing through medical records to see whether he harmed any of the hundreds of patients he treated, authorities said.

Ernest Addo of Austell, Ga., is charged with unlawful practice of medicine and obtaining goods under false pretense, authorities said.

Addo doesn't have a medical license in the U.S. But he assumed a doctor friend's identity, getting a driver's license and presenting the massive amount of paperwork needed to prove he was a doctor. The documents were given to him by the friend in hopes they could open a medical clinic together when the real doctor returned from a yearlong trip to Ghana, Lexington County Sheriff James Metts said.

The real doctor, Arthur Kennedy, said he is embarrassed and devastated by what his friend did.

Addo did have some medical training, and acted enough like a doctor not to raise any serious suspicion beyond one nurse -- interviewed after Addo's Aug. 24, arrest -- who wondered why he consulted ask.com when she questioned his treatment plan, Metts said.

The motive appears to be greed, the sheriff said. Court documents show Addo has a history of financial trouble.

Records obtained by The Associated Press show in the past 20 years, at least two dozen liens have been filed against Addo for around $200,000, including unpaid rent, credit card bills, student loans and taxes. Addo has declared bankruptcy twice.

After Addo's arrest last week at his Georgia home, officers found fake IDs and other documents, and Metts said it appears Addo might have tried to fake his way through other lucrative careers, too. The sheriff wouldn't specify which ones.

"He seems to be a professional con guy," Metts said.

Authorities have said Addo received more than $10,000 for his services but declined to elaborate. One of the jobs also gave him the use of a Mercedes.

Addo, 48, has been jailed in Cobb County, Ga., since his arrest, and neither the sheriff nor jail officials knew if he had an attorney. Addo is refusing to talk to authorities, and both his home phone and cellphone have been disconnected.

Addo faces more than a decade in prison for his current charges, but he could end up in even more trouble. Metts said his investigators are reviewing the medical records of more than 500 patients Addo saw while at four Columbia-area senior centers and a rehabilitation center owned by Agape Senior Primary Care.

Metts said some of those patients died. He said more charges could follow if any of those deaths were linked to Addo's actions.

Addo was hired as a general practitioner and provided the kind of exams patients would receive during a visit to the family doctor. Authorities said he also wrote prescriptions, including some for himself.

Officials at Agape are doing their own review of the care patients received from Addo. They said he never had sole clinical oversight of any patient.

"We have found no inappropriate diagnosis or plan of treatment. We are convinced that all of our patients are safe and receiving proper care," Agape CEO Scott Middleton said in a statement.

Addo also worked as a contract doctor for the South Carolina Department of Mental Health, filling in for a doctor on medical leave. Officials there said they also are reviewing Addo's care and have not found any serious issues.

Patients treated by Addo could not be located by The Associated Press for comment.

Authorities started investigating Addo after he made a small mistake on a death certificate. South Carolina health officials trying to fix the error contacted the doctor Addo was impersonating. He told them he hadn't practiced medicine for a year in the state because he was teaching at a medical school in Ghana.

Officials have refused to release that doctor's name, but Kennedy confirmed his identity was stolen.

Kennedy said he was betrayed by his friend. Addo also obtained credit cards in Kennedy's name, creating an even bigger mess to clean up, the doctor said Wednesday outside his home in Orangeburg.

He said he didn't want to answer detailed questions about what happened until he spoke to a lawyer.

Both Kennedy and Addo are from Ghana. Kennedy ran unsuccessfully for president of the west African nation in 2008. He had a family practice in Orangeburg and spent plenty of time in his homeland, pushing for public health improvements. The two men resemble each other, and Addo used Kennedy's reputation to help get him the doctor jobs. Agape said in a statement it hired him in part because he came highly recommended.

Both Agape and Jackson & Coker, the Alpharetta, Ga., physician recruitment firm that placed Addo with the Department of Mental Health, have promised to help authorities. Metts said it could take months for investigators to go through all the medical records.

Jackson & Coker also is exploring any legal action it could take against Addo and is shocked he was able to obtain all the documents someone would need to prove he was a doctor in the United States, spokeswoman Susan Meyers said.

"He was hired the same way in several different places," Meyers said. "There were no red flags."