Carlos Nuzman, leader of the Rio de Janeiro Olympic Games, will remain incarcerated after the ruling issued on Monday by a federal judge.

Nuzman was arrested last week and placed under provisional detention as part of an investigation by Brazilian and French authorities into alleged vote-buying to win the rights to host the 2016 Rio Olympics.

The judge's ruling changed Nuzman's status from provisional detention to preventive detention. Nuzman's lawyer, Nelio Machado, said he does not know when Nuzman may be released from prison.

The Brazilian prosecutors believe that Nuzman, 75 years old, played a key role in diverting at least two million dollars from a Brazilian businessman to Senegalese Lamine Diack, a former IOC member who helped control African votes.

The Brazilian Olympic Committee was also provisionally suspended and its accounts frozen. Nuzman was excluded from the IOC commission inspecting Tokyo's preparations for the 2020 Games.

Nuzman's detention is the latest blow to the troubled Rio Olympics, which have suffered from low ticket sales, budget cuts, and debt that required a government bailout to hold the Paralympic Games. Many of the facilities built for the Games are now unused.

Also on Monday, the Swiss prosecutor's office agreed to assist Brazilian authorities in the investigation.

The Swiss Federal Prosecutor's Office stated that the request submitted by Brazil last week is currently being executed.

Although the details were not disclosed, Swiss prosecutors can potentially share information about bank accounts and financial transfers from banks in the country.

Brazilian prosecutors have indicated that Nuzman, who led the 2016 Olympic bid and organizing committees, had hidden 16 gold bars in a vault in Geneva.