French police released former International Monetary Fund chief Dominique Strauss-Kahn on Wednesday after nearly 30 hours in custody for questioning about a suspected hotel prostitution ring.
Strauss-Kahn, 62, is expected to be summoned again next month by judges who will decide if there is enough evidence to press charges in the case, judicial officials said.
The marathon police questioning returned the media spotlight onto the sexual dalliances of Strauss-Kahn, a one-time French presidential hopeful whose political career all but ended last spring over a New York hotel maid's allegations that he sexually assaulted her.
French police are investigating a suspected prostitution ring that has implicated police and other officials. They have questioned prostitutes who said they had sex with Strauss-Kahn during 2010 and 2011 at a luxury hotel in Paris, a restaurant in the French capital and also in Washington, D.C., where he lived while working for the Washington-based IMF.
Strauss-Kahn's name surfaced in the investigation last fall, and he has welcomed the chance to tell his side of the story.
Police asked Strauss-Kahn about suspicions centering on complicity in organized prostitution at hotels in Lille and Paris, officials said. One of his lawyers has acknowledged Strauss-Kahn took part in orgies, but didn't know the women attending were prostitutes.
Two men with ties to Strauss-Kahn have been put under preliminary investigation on charges including organizing a prostitution ring and misuse of corporate funds.
Television footage showed police keeping reporters behind metal barriers as a sedan with tinted windows took Strauss-Kahn away from the station in northern city of Lille.
"He is entirely satisfied to have been heard," his lawyer Frederique Beaulieu told reporters. She said Strauss-Kahn's questioning took place "with great serenity" and he answered all questions asked.
"The fact that he is released free is a very good thing," she said.
Under French law, police could question Strauss-Kahn for up to 96 hours, after which a judge would have to intervene to decide whether he could be held further.
His lawyers have denounced a "media lynching" of Strauss-Kahn in the prostitution case, and insist he has been unfairly tried in the court of public opinion.
Strauss-Kahn's political career was derailed by the sexual assault accusation in New York City and his subsequent resignation from the IMF in May.
U.S. authorities eventually dropped the charges when prosecutors said the hotel maid's testimony was unreliable. Strauss-Kahn has called the encounter "inappropriate."
French newspapers have dubbed the prostitution investigation "The Carlton Affair" after the name of the expensive Lille hotel where some encounters allegedly took place. Investigators are seeking to discover if prostitutes were paid using corporate funds from French construction company Eiffage.
The "Carlton affair" is unconnected to the New York case. Despite prosecutors' doubts, the hotel maid has insisted she was truthful about the encounter and is pursuing claims against Strauss-Kahn in a civil lawsuit.
Jamey Keaten contributed to this report.