Topeka ? David Wittig, former chief executive officer of Westar Energy Inc., filed a motion Thursday asking that his second trial on federal looting charges be put on hold while he asks an appeals court to remove the presiding judge.

U.S. District Judge Julie Robinson last week refused to recuse herself from the second trial of Wittig and co-defendant Douglas Lake. The trial is scheduled to begin May 9 in Kansas City, Kan.

Wittig and Lake, Westar’s former chief strategy officer, claim Robinson is biased against them because of comments she made during and after their first trial and a series of conditions she has placed on their second trial on charges of fraud, money laundering and circumventing internal controls at the Topeka-based utility.

The first trial ended in December when Robinson declared a mistrial after the jury failed to reach a verdict on more than half the charges.

On Thursday, attorneys for Wittig said they planned to ask the 10th U.S. Circuit Court of Appeals, which covers Kansas, to review the matter. The defense lawyers said they wanted the trial delayed until the court made a decision.

A spokesman for the U.S. Attorney’s Office said prosecutors agreed with Robinson’s decision not to recuse herself and would respond to the motion.