NEW ORLEANS (AP) — Former New Orleans Mayor Ray Nagin has asked a federal judge to postpone his bribery trial indefinitely so his attorney can explore whether the case has been tainted by alleged prosecutorial misconduct.

Nagin's trial is scheduled to start on Oct. 28, but his lawyer argued in a court filing Thursday that he needs more information about a Justice Department probe of anonymous online comments posted by at least three federal prosecutors.

On Tuesday, U.S. District Judge Kurt Engelhardt cited the posts as evidence of "grotesque" prosecutorial misconduct. He ordered a new trial for five former New Orleans police officers convicted of civil rights violations stemming from deadly shootings on a bridge following Hurricane Katrina.

Nagin pleaded not guilty in February to bribery charges.