Prosecutors angrily deny claims by Roman Polanski's lawyers that they tried to conceal evidence in his 32-year-old sex case, and they have renewed demands that an appeals court order him to return to the United States for sentencing.

Two prosecutors who handle appellate matters for the district attorney's office argue in a 26-page brief filed Tuesday that allowing Polanski to avoid extradition from Switzerland hurts the integrity of the judicial system more than revelations of alleged misconduct by a now deceased judge.

They also claim there has been a misinterpretation of an extradition treaty with Switzerland and that Polanski should be returned for a court hearing in Los Angeles.

The 76-year-old film director fled the U.S. in 1978 after pleading guilty to unlawful sexual intercourse with a minor. He remains under house arrest at his chalet in Switzerland.