AUSTIN, Texas — A court hearing to determine whether a man executed in 2004 was innocent of burning to death his three young daughters was postponed Wednesday when prosecutors asked the judge to take himself off the case.

Cameron Todd Willingham's family is seeking to have his name cleared amid claims that the evidence arson investigators used in his 1992 trial was based on flawed science.

If the court exonerates Willingham of killing his three daughters he will be the first person officially declared innocent after being executed in the modern era of US capital punishment.

Prosecutors asked State District Judge Charlie Baird to recused himself because he presided over two of Willingham's appeals and was given an award by an anti-death penalty group.

The hearing is set to resume on October 14 when Baird will announce whether he will continue to preside over the case.

Protestors carrying signs declaring Williamson's innocence demonstrated outside the courthouse and packed the courtroom to observe the proceedings.

"This is the first time we've had a chance for someone who has been executed to prove their innocence," said Gloria Rubic of the Texas Death Penalty Abolition Movement.

"I want to be able to shout from the rooftops that Todd was innocent."

Willingham's former wife held a press conference earlier in the day at which she insisted he was guilty and had confessed to her shortly before his execution.

"I am here today to stand up one last time on behalf of my daughters," Stacy Kuykendall told a wall of news cameras.

"He stood and watched while their tiny bodies burned."