On Monday, Swiss authorities decided not to extradite Oscar-winning film director Roman Polanski to the United States, where he would face a sentence from a 30-year-old crime involving the rape of a 13-year-old girl.

Mr. Polanski was also released from his seven-month house arrest at "the Milky Way," his three-story vacation chalet in the luxurious Alpine resort town of Gstaad.

The Swiss Federal Department of Justice and Police said the U.S. extradition request was possibly flawed since American authorities had known of his frequent presence in Switzerland since 2006 yet had never acted on it.

On his way to a film festival in Zurich in September of last year, Mr. Polanski was picked up and arrested on the request of California authorities. Mr. Polanski, who had not set foot in the U.S. since 1978, had assumed that he did not face any arrest risk in Switzerland, which he had frequently visited in the past.

"Roman Polanski would not have decided to go to the film festival in Zürich in September 2009 if he had not trusted that the journey would not entail any legal disadvantages for him," the Swiss justice ministry said.

The film director, however, was not idle during his house arrest and was able to put the final touches on his most recent film, the political thriller "The Ghost Writer," during that period.