This Aug. 12, 2013 file photo shows the office of Farid Fata in Oak Park, Mich.  (AP Photo/Carlos Osorio)

Speaking with a lisp, Robert Sobieray told Michigan state legislators on Tuesday he lost all but two teeth after a 24-month chemotherapy treatment for a cancer he didn’t have.

The treatment was prescribed by Farid Fata, a Detroit-area oncologist dubbed the “death doctor” after the FBI uncovered a six-year fraud scheme that bilked taxpayers out of millions in Medicare dollars. Fata, 49, prescribed cancer treatments to patients who didn’t have cancer and sent other sick patients in for unnecessary, painful treatments. Some of them died.

“She never stood a chance in this battle, as she was being poisoned and tortured for personal greed,” Michelle Mannarino said of her mother, according to the Detroit News. She was a patient of Fata’s who died in 2010. “Several times when I had researched and questioned his treatment,” she told a Michigan House committee, “he asked if I had fellowshipped at Sloan Kettering like he had — which of course, I hadn’t, so I deferred to the doctor.”

“In order to make sense of my mother’s death, I need to prevent this from happening in the future,” Mannarino added, according to WXYZ.

Sobieray, Mannarino and others told their horror stories to Michigan legislators considering a bill that would authorize state officials to permanently revoke the medical licenses of doctors who defraud patients for financial gain.

Fata’s medical license was revoked in January but could be reinstated in five years under current law. His former patients don’t think he should ever be allowed to practice again.

The Michigan state house health policy committee approved the proposal to tighten the rules. Next it will go before the full house for a vote.

Fata pleaded guilty in U.S. District Court earlier this month to 13 counts of health-care fraud, one count of conspiracy to pay or receive kickbacks and two counts of money laundering. He will be sentenced in February and faces up to 175 years in prison.

“It is the most egregious case of health-care fraud I have ever seen,” U.S. Attorney Barbara McQuade said in a statement reported by Click On Detroit. “I think what makes this case different is this is not just a case of a doctor billing Medicare for extra treatments or treatments that weren’t rendered in order to make a profit. This was a case of a doctor exploiting patients, using them as commodities in order to make money.”

Between 2007 and 2013, Fata submitted $225 million in Medicare claims, $109 million of which was for chemotherapy. Medicare paid out more than $91 million, according to the indictment. He also billed private insurers for unnecessary services.

This is how the scam worked: Fata filed claims for services that weren’t medically necessary, then referred those patients to home health care and hospice providers in exchange for kickbacks.

According to the complaint, employees told investigators that Fata prescribed chemotherapy, which can be excruciatingly painful, for patients nearing the end of their lives, while the norm is to let such patients die in peace.

“I was told every single month that I was terminal. I rushed to take trips and try to make memories for my grandkids, gave things away, watched my husband go into depression … and everything was a lie,” former patient Patty Hester, 60, told the Oakland Press.

In the complaint, an employee also describes one case where a patient came to see Fata after falling and hitting his head. Fata directed an employee to give him chemotherapy before taking him to the emergency room. The patient later died from his head injury. In a similar instance, Fata directed chemotherapy be administered to two patients who had other serious medical conditions before he would send them to the hospital to treat their real illness.

He also prescribed chemo for cancer patients in remission and diagnosed people with anemia and fatigue to justify unnecessary blood treatments.

When patients questioned their treatment or seemed uneasy about it, Fata prescribed Xanax.

How did he get away with it for so long? Instead of raising suspicion by sending patients to outside pharmacists and practitioners, Fata did as much as possible in-house. He owned his own medical diagnostics company and PET scan machine. Fata usually diagnosed people with blood cancers, one employee said, because it was easier to falsify than a tumor diagnosis, the complaint said.

The investigation into Fata was a joint effort involving the FBI, IRS, and Department of Health and Human Services.