Polanski pleaded guilty to having sex with a 13-year-old girl in 1977, but fled America a year later before he could be sentenced.
He was arrested in Zurich, Switzerland last year (09) and is currently being held under house arrest while he awaits deportation to the U.S.
In January (10), the filmmaker lost his fight against extradition and a Los Angeles judge ruled he must return to be sentenced.
But Polanski's lawyers launched a fresh appeal on Thursday (18Mar10), filing papers at Los Angeles Superior Court, in which it is claimed new evidence demonstrates that a prosecutor was aware of alleged misconduct by the judge in the 1977 case.
The Rosemary's Baby director's legal team is now requesting that a special counsel investigates the allegation, claiming former Deputy District Attorney Roger Gunson gave secret testimony this year (10) on the judge's conduct.