Renate Langer, a 61-year-old former German actress, has filed a report with the Swiss police accusing Polanski of raping her when she was 15 at a house in Gstaad in February 1972, according to The New York Times.
Langer is now the fourth woman to publicly accuse the "Rosemary's Baby" director of sexual assault.
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The public prosecutor's office is still deciding if she can pursue a criminal complaint.
Langer said she came forward in hopes that the law would allow her claim to be investigated. She also explained that she kept quiet about the incident at the time, mostly in fear of her parents' reaction.
"My mother would have had a heart attack. I felt ashamed and embarrassed and lost and solo," she told The New York Times.
The new report comes after the director, 84, spoke out about his 1970s rape accusation in a rare interview, saying that he feels he has completed his sentence.
Polanski is currently in Zurich to promote his newest film, "Based on a True Story", which will make its premiere at the Zurich Film Festival.