The Los Angeles county district attorney's office sudden decision last weekend to seek the extradition of Roman Polanski from Switzerland on a 31-year-old charge of statutory rape appears to have been triggered by a politically embarrassing documentary providing damaging evidence of misconduct by the judge who conducted the original trial.

Earlier this year, Polanski's lawyers sought to have the long-standing charge against him dropped because of legal irregularities highlighted in Marina Zenovich's Roman Polanski: Wanted And Desired. A Los Angeles superior-court judge rejected the application because the Polish director, who fled to France in 1978 rather than face 50 years in jail, failed to appear in court in person. The judge agreed, however, that there was "substantial misconduct" in the original hearing and an appeal is pending.

Zenovich's film was screened at Zurich Film Festival when Polanski's arrest by Swiss authorities prevented him attending a major retrospective of his work. It in no way seeks to condone Polanski for the statutory rape of 13-year-old model Samantha Gailey (now Samantha Geimer) after a magazine shoot at Jack Nicholson's home in 1977. He confessed his guilt for the crime in a plea bargain agreed by judge Laurence J Rittenband with the assistant district attorney Roger Gunson, who prosecuted the case, and defence attorney Douglas Dalton.

Zenovich uses eyewitness testimony to portray Rittanband – who was removed from the case on a joint motion by Gunson and Dalton, and died in 1993 – as a publicity seeker less concerned with justice than with his own image. Geimer, now married and living in Hawaii, accuses Rittanband of "orchestrating some little show that I didn't want to be in".

Rittenband gave a press conference during the case, held sham sessions ("like a mock trial", according to Dalton) and talked with outsiders, even calling a reporter to his chambers to ask, "What the hell should I do with Polanski?" Upset by media hostility over the plea bargain Polanski agreed to in order to save Geimer the ordeal of a court appearance – and under which he was to get parole after serving a 90-day "evaluation" sentence at Chino State Prison – Rittenband broke his word, leading to Polanski fleeing the country. "I'm not surprised he left the country under those circumstances," says Gunson.

"A lot of people can't get past the fact that Polanski fled," Zenovich said when her documentary premiered at Cannes Film Festival. "I just wanted to present the facts of the case." Both her parents are lawyers – her father was also a serving Californian senator, which perhaps explains her scrupulously balanced treatment. "I never felt it was up to me to decide or make a judgement. If anything I was worried that I could be too easy on Polanski."

Zenovich is best known for her documentary Who Is Bernard Tapie?, in which she tracked down, Michael Moore-style, the disgraced mayor of Marseilles ("I have a reputation for never giving up, I should have been a detective"). She was drawn to the Polanski case when Geimer publicly forgave Polanski on the Larry King Live show in 2003 following speculation about whether he would be able to return to LA if nominated for an Oscar for The Pianist. "Her lawyer said that what happened in the case was a shameful day for the American judicial system."

Zenovich sought to interview Polanski, now a French citizen, but didn't hear back. "Then I was talking to his friends and I was hearing that he was telling them that it was OK to talk to me. His agent eventually got back to me to say Polanski was very sorry but he felt it would like self-promotion to talk to me."

Polanski (76) is still in "provisional custody" in Switzerland, where he is likely to remain until his case is resolved.

Filmmakers led by Cannes Film Festival director Thierry Fremaux are rallying to his support. And Zenovoich? "I'm thinking of making a documentary about Nicolas Sarkozy."

Polanski agreed to pay off victim

Film director Roman Polanski agreed to pay his sex assault victim $500,000 dollars (€343,000) to settle a lawsuit 15 years after he fled the US, according to court documents.

The deal between Polanski and Samantha Geimer was reached in October 1993. The terms of the settlement were confidential, but the amount was disclosed in court documents because of a two-year struggle to get Polanski to pay.

Court records do not indicate if Polanski, now 76, ever paid. The last court filing in August 1996 shows Polanski owed Geimer $604,416.22 (€414,000), including interest.

Polanski's lawyer, David Finkle, said he could not remember details of the case and declined to comment.

Geimer and her family have not returned calls seeking comment.

Polanski pleaded guilty to unlawful sexual intercourse with Geimer, who was 13 at the time, in 1977. He fled in 1978 before he was sentenced and is being held in Switzerland after his arrest there last weekend on a fugitive warrant in the case.