A doctor at the center of a steroid investigation involving Carolina Panthers (search) players was suspended by the state medical board, which called the practitioner a "serious threat" to public health.

The South Carolina Board of Medical Examiners said Dr. James Shortt (search) prescribed the steroid testosterone (search) to four unidentified male patients "in doses and frequencies that were extremely unlikely to have been prescribed with any legitimate medical justification."

An accompanying document from a state Labor Licensing Department investigator said the dosage and refill levels for the testosterone "provide a strong indication" that they were used for medically unnecessary purposes such as increasing muscle mass.

A medical board spokesman declined to say whether any of the four males cited in the suspension order were Panthers players.

The order, announced Thursday after a secret vote a day earlier, also cited the 2004 deaths of two patients whose families have filed malpractice lawsuits.

Katherine Bibeau (search), who had multiple sclerosis, died three days after receiving intravenous hydrogen peroxide. Michael Bate (search), who died of prostate cancer, also received the peroxide injections and was allegedly told by Shortt how to get and take an illegal cancer drug.

Shortt, a traditionally trained M.D. who turned to alternative medicine, has been under investigation for nearly a year by state and federal authorities probing illegal steroid prescriptions.

Shortt denied any wrongdoing. "I'm annoyed," he told The Charlotte (N.C.) Observer for Friday editions.

CBS News reported last month that three Carolina Panthers players filled prescriptions from Shortt for banned steroids less than two weeks before the team played in the 2004 Super Bowl.

The suspension order said Shortt's actions, including the intravenous hydrogen peroxide infusions, "render him unfit to practice medicine and constitute a serious threat to the public health, safety or welfare."

Katherine Bibeau's widower, David Bibeau, said the suspension gave him a sense of vindication.

"It's taken too long, but I am relieved that finally the public is being protected," he said.

Shortt has not decided whether to contest the suspension, his lawyer Ward Bradley said. Meanwhile, the board will continue its investigation and decide whether to permanently revoke his license, medical board spokesman Jim Knight said.