Newly released documents have shed light on how fugitive film director Roman Polanski came to be arrested during a trip to Zurich last month.The AP news agency said e-mails show that the Swiss authorities tipped off their US counterparts that Polanski, 76, was preparing to travel to Zurich.
The filmmaker was held as he travelled from France to collect an award.
He has been wanted in the US since pleading guilty to unlawful sex with an underage girl and then fleeing in 1978.
The US authorities have so far declined to say how they learned of Polanski's trip to Zurich.
But the e-mails revealed by AP, following a public records request, show that the information came from the Swiss Federal Office of Justice.
After receiving the tip-off, US federal officials alerted prosecutors in Los Angeles, who drafted an arrest warrant, according to AP.
Correspondents say is not clear why Switzerland chose to pursue Polanski now, when the director has been a frequent visitor to that country.
He has lost an appeal to be released on bail and is currently being held in a Swiss jail ahead of his possible extradition to the United States.
