Brazilian officials said have that the country’s Olympics chief was the “lynchpin” in a plot to bribe the International Olympic Committee into awarding Rio de Janeiro last year’s Games.

Brazilian police on Tuesday said in a statement they were probing “an international corruption scheme” aimed at “the buying of votes for the election of (Rio) by the International Olympic Committee as the venue for the 2016 Olympics.”

Revealing a nine-month investigation spanning several countries and dubbed “Unfair Play,” police said Carlos Nuzman had been taken in for questioning and his house searched.

Nuzman, who was the point-man for Rio’s successful bid to become the first South American host of the Olympics, left his house in Rio’s posh Leblon neighbourhood while police officers exited with bags of evidence.

Prosecutors said Nuzman was detained to give testimony and although not arrested he had his passport confiscated.

An arrest warrant was issued for Arthur Soares, a businessman who won lucrative pre-Olympics contracts from Rio’s government when it was headed by the now imprisoned state governor Sergio Cabral. He lives in Miami.

A former Soares associate, Eliane Pereira Cavalcante, was arrested in Rio and 11 properties were subjected to search and seizure raids. One of them was in Paris, French authorities said.

In Lausanne, Switzerland, an IOC spokesman appeared to have been taken by surprise.

“The IOC has learned about these circumstances from the media and is making every effort to get the full information,” the spokesman said.

“It is in the highest interests of the IOC to get clarification on this matter.”

Brazilian investigators have worked closely with a similar French probe into the vote buying and French officials, including well-known anti-corruption Judge Renaud Van Ruymbeke, attended the raid on Nuzman’s home.

The United States and other countries have also been involved as officials tracked down alleged bribe payments made in offshore bank accounts, Brazilian prosecutors said.

Prosecutor Fabiana Schneider told a press conference that Soares, known in Brazil as “King Arthur,” allegedly bribed the son of Senegalese IOC member Lamine Diack before the 2009 vote in which Rio beat Chicago, Madrid and Tokyo to win the 2016 Games.

Diack, who was head of the International Association of Athletics Federations (IAAF) at the time, had considerable influence over African votes on the IOC.

Nuzman, Schneider said, had been the “lynchpin” between Soares and the son, Papa Massata Diack.

“In this context and putting all the elements together, we can come to the conclusion that Sergio Cabral and his criminal organization, including Arthur Soares, effectively bought the vote for Rio de Janeiro to host the Olympic Games,” she said.

The Rio games were generally credited with being a sporting and organisational success, but revelations of massive corruption during the preparations and now even in the naming of the host city have tarnished the legacy.

In June, Cabral was sentenced to 14 years in prison. He was convicted of bribery and money laundering, including participation in the embezzlement of 220 million reais ($64 million) from public works projects such as Rio’s iconic Maracana football stadium.

Schneider said the Games had been used as a “trampoline” for corruption.

A lawyer for Nuzman, Sergio Mazzillo, said his client was “calm.”

He told journalists that Nuzman “says he did not act in an irregular way, that he did nothing wrong during the campaign.”

The scandal comes as Brazilian law enforcement pursues the country’s biggest ever anti-corruption fight in a probe known as “Car Wash,” which has uncovered a huge web of embezzlement and bribery at top levels of politics and business.