PARIS -- Former IMF chief Dominique Strauss-Kahn has been released from a French police station after nearly two days of questioning over a suspected hotel prostitution ring.

Judicial officials say Strauss-Kahn, a one-time French presidential hopeful whose political aspirations were derailed by a May 2001 sexual assault accusation in New York City, will be summoned again next month by three judges who will decide if there is enough evidence to file charges in a case centering on the alleged prostitution ring in France and Belgium.

Strauss-Kahn held in French prostitution ring

French TV footage showed police restraining reporters behind metal barriers as a tinted-window sedan carrying Strauss-Kahn left the police station in northern city of Lille.

The investigation is focused on a prostitution ring that allegedly supplied clients of Lille's luxury Carlton Hotel. Police want to establish whether Strauss-Kahn knew that women at parties he attended in Paris and Washington were prostitutes.

Strauss-Kahn believed he was participating in swingers' parties and had no reason to suspect that the women were prostitutes, his lawyer Henri Leclerc has said previously. Consorting with prostitutes is legal in France; however, Strauss-Kahn could be charged for benefiting from misappropriated company funds if investigators conclude he attended sex sessions with prostitutes that company executives paid for out of expense accounts, according to Britain's The Guardian.

Sex scandal
Strauss-Kahn's job as head of the International Monetary Fund, as well as his presidential ambitions, came to an end last spring when he was accused of trying to rape a Guinean chambermaid in a Manhattan hotel suite. Criminal charges were later dropped when it emerged that the maid, Nafissatou Diallo, was an unreliable witness. Diallo is now pursuing him in a civil action.

Separate attempted-rape accusations by a Parisian writer also were shelved by French police on October 13 -- three days before Strauss-Kahn's name surfaced again in the Lille investigation.

Nancy Ing from NBC News and Reuters contributed to this report.

More from msnbc.com and NBC News:

• Former 'Amazing Race' producer found dead in Uganda
• Palestinians cheer pending release of hunger striker
• Wildlife officials fear 'epidemic' in rhino poaching
• Journalist beatings erase optimism in China