The Hippocratic Oath (search) doctors swear to save lives, not end them. But one doctor accused of doing just that also happens to be the governor of Kentucky, and a lawmaker willing to sign execution orders on death row inmates.

"There is a distinct difference between acting as a physician for a patient and acting as a governor for the people of the commonwealth of Kentucky," Gov. Ernie Fletcher, a former family physician and U.S. congressman elected to the state's highest office last year, told FOX News.

Last month, Fletcher signed the death warrant for 51-year-old Thomas Clyde Bowling (search), who was convicted in 1990 of killing a couple outside their dry cleaning store in Lexington, Ky. Death penalty opponents, including Amnesty International and the American Civil Liberties Union, protested the governor, arguing that the case against Bowling had flaws and that he is mentally retarded. The U.S. Supreme Court ruled in June 2002 that executing people with mental retardation is unconstitutional. Kentucky already had the prohibition on the books when the court ruled.

But opponents to Bowling's execution also made the appeal that signing paperwork resulting in death violates Fletcher's oath as a doctor.

"The basic Hippocratic Oath is 'do no harm,' and execution does irreparable harm," said Dr. Stewart Urbach at the University of Louisville.

Fletcher said he was simply fulfilling his responsibility as governor.

"I felt the jurors made a sound decision, and I wanted to recognize they made a sound decision and acknowledge that by signing the death warrant," Fletcher said.

Now, a group of doctors has asked the state medical board to investigate whether Fletcher violated the rules of the Kentucky Medical Association (search), which licensed Fletcher. The state guidelines are in sync with guidelines from the American Medical Association (search), which say that physicians shouldn't participate in executions. The AMA defines an execution as anything that assists or contributes to the death of a condemned prisoner.

"That is a direct violation of Kentucky law as well as the AMA ethics code and Kentucky medical Association ethics code," said Dr. Steven Lippman at the University of Louisville.

Bowling's November execution date was stayed by two courts, including the Kentucky Supreme Court, which is still considering a claim from Bowling's attorney that her client is mentally retarded and therefore his sentence should be commuted.

Meanwhile, officials at the Kentucky Medical Association say the KMA's board will rule on Fletcher's license early next year. Fletcher said he's not worried about the outcome.

"I think reason will rule here, and I feel we have acted in a very reasonable way," he said.

Click in the box near the top of the story to watch a report by FOX News' Jeff Goldblatt.