Mounting friction between the administration and House State Government Committee Chairman Charles Geveden prompted the administration to hold a news conference blasting the investigation. Mark Birdwhistell, a former CHA Health executive, denied any wrongdoing and said he would testify before the committee if asked.

"In every way my actions are legal, moral and ethical," Birdwhistell told reporters. "For anyone to insinuate that is only false, and my personal feeling is it's very mean-spirited."

Fletcher called the General Assembly into a special session last week, hoping it could improve upon the administration's 2005 health-insurance plan, which has been met with a public outcry and a threatened teachers' strike this month if benefits aren't restored.

Geveden's committee has been holding hearings and gathering testimony on Birdwhistell's involvement. No allegations have been made, but the committee approved a resolution Tuesday that would allow it to summon people under oath.

Tension exploded Tuesday during a committee hearing as some of Fletcher's top-ranking staff and cabinet secretaries sat in the audience.

Fletcher's chief of staff, Daniel Groves, said later that "Geveden moved from a witch hunt to the possibility of Salem witch trials" by broaching the possibility of having people testify under oath.

Administration officials asked that Birdwhistell be allowed to answer questions from the committee. Geveden refused but said Birdwhistell could testify later.

Until January, Birdwhistell was chief executive officer at CHA Health, which is 84 percent owned by the University of Kentucky. He is now an undersecretary in the Cabinet for Health and Family Services.

CHA is one of four insurance companies awarded state contracts to carry next year's health-insurance plan.

The committee is also investigating the role other former CHA Health executives played in negotiations that led to the state's new health plan.