A Texas prosecutor accused of bias for describing an executed man as a "guilty monster" defended his comments Friday, while his colleagues on a commission investigating the case said he might have jeopardized the integrity of their inquiry.

Williamson County District Attorney John Bradley said lawyers trying to clear Cameron Todd Willingham's name are using the case to further their effort to abolish the death penalty. He also argued that he has a First Amendment right to state his opinion.

"We are being used, and we should recognize that," Bradley said. "When do we get to respond to those lies? Who is going to correct the record?"

Willingham was convicted in 1992 of capital murder in the deaths of his three daughters and executed in 2004.

Bradley chairs the Texas Forensic Science Commission, which is investigating whether fire investigators committed professional misconduct in determining arson caused the 1991 Corsicana house fire that killed Willingham's daughters. At least nine fire experts have said the fire was an accident, not arson.

Other commission members said Bradley's remarks to The Associated Press, in which he described Willingham as a "guilty monster," raise questions about the impartiality and integrity of their inquiry.

"There is a difference between correcting the record and making the type of statement we are talking about," said Sarah Kerrigan, the laboratory director at the Sam Houston State regional crime lab.

But Bradley then referred to the Innocence Project's effort to clear Willingham as "politics and a circus sideshow."

"Texans deserve to have a prosecutor's voice included in the discussion of forensic science, a voice that can include concern for the victims of crime and not just the perpetrators of crime," said Bradley, who was appointed to the chairmanship last year by Gov. Rick Perry.

Stephen Saloom, the policy director of the New York-based Innocence Project, said Bradley shows "a critically important lack of objectivity" in his approach to Willingham.

"His job here is not to be the DA and the friend of the governor," Saloom said.

Bradley, who raised his voice repeatedly, dismissed Saloom as a "New York lawyer" making "personal attacks rather than legal arguments."

Bradley's leadership has been questioned since last year, when the governor sacked three members of the forensic commission just days before it was to review reports that cast doubt on the arson finding. Perry installed Bradley, a conservative ally, as the new chairman. Bradley canceled the subsequent meeting and since has sought to close the inquiry.

On Thursday, two fire experts testified at a special court of inquiry hearing unrelated to the forensic panel's inquiry, saying the Willingham fire was an accident. The judge overseeing that hearing has the power to declare Willingham innocent.

An Austin appeals court, however, granted an emergency stay that will prevent the judge from ruling for at least one week and could end the proceeding altogether.

If the judge clears Willingham, it would mark the first time an official in the nation's most active death penalty state has formally declared that someone was wrongfully executed.

The commission took no action Friday on Willingham. However, members are trying to arrange a November meeting that would hear live testimony from fire experts who have studied the case.

Bradley continued to criticize the effort to clear Willingham after the meeting.

"I think it's pretty ridiculous to have this court of inquiry at the same time we're doing this," Bradley told reporters. "I think the public can see it for the sham that it is."