BATON ROUGE - A pain management doctor and his billing supervisor pleaded guilty Monday over a Medicare fraud scheme.

Dr. John Eastham Clark pleaded guilty Wednesday to count one of an indictment charging him with conspiracy to commit health care fraud. Charlene Anita Severio, who served as Clark's billing supervisor, also pleaded guilty to an indictment charging her with conspiracy to commit health care fraud and wire fraud and two counts of the indictment charging health care fraud.

Prosecutors alleged Clark and Severio ran a $4.4 million fraud scheme in which bills were faked to indicate false surgical procedures and other unnecessary tests.

The two were just some of those caught in a sweeping investigation that involved 400 people in all across forty-one judicial districts. In 2015, WBRZ filmed as the FBI raided Clark's business on Bluebonnet Boulevard.

More than three years ago, documents obtained by the WBRZ Investigative Unit showed Doctor John Clark was then one of the top prescribers for oxycodone HCL, a powerful pain medication, in Louisiana. A public watchdog group also reported Clark filed more than 468 Medicare claims for oxycodone. In 2015, he was ranked 23rd out of all doctors in the state for issuing the drug.