An Atlanta-based physician was sentenced Monday to federal prison for filing more than $1 million in false claims for services he did not perform, the U.S. Attorney’s Office said.

Robert E. Windsor, 55, of Cumming, claimed for more than three years between January 2010 and July 2013 that he had monitored the neurological health of patients during surgery when he actually had an unqualified medical assistant do the work, U.S. Attorney’s Office spokesman Bob Page said in a news release Monday.

The assistant used Windsor’s log-in credentials to make it appear as if he was monitoring the surgeries when he was not. Windsor then billed health insurers over $1 million for the services he never performed.

Assistant Special Agent in Charge George Crouch, with the Atlanta FBI office, called Windsor’s willful deceit reprehensible. He thoughtlessly put patients’ health at risk to profit from the system, Crouch said.

In total, after collecting reimbursements from insurers, Windsor was paid more than $1.1 million for monitoring services he did not perform. Investigators uncovered Windsor’s fraud through analysis of Medicare billing data and complaints to the HHS-OIG Hotline at 800-HHS-TIPS.

Windsor was sentenced to three years and two months in prison to be followed by three years of supervised release. He was ordered to serve 200 hours of community service, and to pay $1,169,580 in restitution to health insurers.