U.S. authorities accused Jacques Roy on Tuesday of "selling his signature" to collect Medicare and Medicaid payments for work that was never done or wasn't necessary. Others charged in the scheme are accused of fraudulently signing up patients. Roy, 41, a doctor who owned Medistat Group Associates in DeSoto, Texas, faces up to 100 years in prison if he's convicted of several counts of health care fraud and conspiracy to commit health care fraud. Six others, including the owners of three home health service agencies, are also charged. More than 75 agencies linked to Roy have had their Medicare payments suspended. The scheme was the largest dollar amount by a single doctor uncovered by a task force on Medicare fraud, authorities said.