The remark during a hearing in U.S. District Court in Salt Lake City followed other complaints about Ward's handling of the case from Johnson, who has waged a campaign against prosecutors and investigators through websites, social media and the news media that accuses them of misconduct.
U.S. Magistrate Judge Paul Warner told Mumford if he believed there had been misconduct he should spell out his concerns in the form of a motion.
"There are ways to raise issues of prosecutorial misconduct," said the judge, who has issued a gag order against the attorneys, Johnson and the others prohibiting them from speaking or posting information publicly about the case.
Johnson, I Works and others were sued by the Federal Trade Commission in December 2010 for allegedly failing to properly disclose charges and using false advertisements to entice online consumers to buy information on "make-money schemes" and "stay-healthy programs" and how to obtain government and private grants.
He was hit with a single criminal charges in 2011 but a new indictment was handed up earlier this year with 86 charges against Johnson and four others after a plea bargain agreement stalled.
The Thursday hearing mostly involved issues of when prosecutors would turn over more evidence to defense attorneys and in what form. But Warner said the high-profile case was not yet ripe enough to set a trial date and instead scheduled another hearing for January.
Mumford's complaint concerned Ward's actions during a deposition of a witness in the civil case pending against Johnson, I Works and others in Las Vegas.
Prosecutors and investigators pursuing the bank fraud, money laundering and conspiracy charges against Johnson and the four others have been sitting in on depositions with witnesses in the Las Vegas lawsuit brought by the Federal Trade Commission. That case also remains pending and no trial date has been set.