The Swiss Attorney General has opened criminal proceedings against Fifa president Sepp Blatter in the heart of the Zurich HQ he has dominated as president for 17 years, as the ongoing corruption crisis gripping world football took another dramatic turn.

The office of the attorney general said in a statement that it had interrogated Blatter following a meeting on Friday of the Fifa executive committee.

At the same time Michel Platini, the Uefa president who is hoping to replace him next year, was heard "as a person asked to provide information”.

Fifa HQ was also searched and data seized from Blatter’s office, causing a scheduled press conference to be cancelled amid fevered speculation.

"On the one hand, the OAG suspects that on 12 September 2005 Mr. Joseph Blatter has signed a contract with the Caribbean Football Union [with Jack Warner as the President at this time]; this contract was unfavorable for Fifa. On the other hand, there is as suspicion that, in the implementation of this agreement, Joseph Blatter also violated his fiduciary duties and acted against the interest of Fifa and/or Fifa Marketing & TV AG,” said the office of the Swiss attorney general, Michael Lauber.

That is believed to relate to the television contract unearthed by Swiss broadcasters that showed Blatter had agreed to sell TV rights to the disgraced former Fifa heavyweight Jack Warner at below the market rate.

"Additionally, Mr. Joseph Blatter is suspected of a disloyal payment of 2m Swiss francs to Michel Platini, President of Union of European Football Associations (UEFA), at the expense of Fifa, which was allegedly made for work performed between January 1999 and June 2002 ; this payment was executed in February 2011.”

As the net has closed around Blatter, who has refused to travel to any countries with an extradition treaty with the US since the scandal broke, he has cut an increasingly remote figure.

"As for all defendants, the presumption of innocence applies for Mr Joseph Blatter,” said the Swiss Attorney General. Blatter has always denied any wrongdoing.

Lauber confirmed last week that it was looking into the TV contract signed by Blatter and Warner as part of its wider investigation, which began as a probe into the award of the 2018 and 2022 World Cups.

In May, seven Fifa executives were arrested in the lobby of the Baur au Lac hotel as American prosecutors outlined charges of money laundering, racketeering and fraud against 14 individuals including nine high ranking football officials.

Of the 14 Fifa officials indicted in May, 13 have been arrested of whom three have been charged in US courtrooms and 10 await extradition.

On Thursday, Fifa handed over emails from his longstanding right hand man Jérôme Valcke, having blocked access even as Blatter pledged support for American and Swiss investigations of corruption.

Valcke was suspended last week in the wake of allegations that he had profited from World Cup tickets sold above face value. He denies the allegations.

The embattled governing body should cooperate "no matter how close to home those investigations get,” Blatter, who is targeted by both criminal cases, had said earlier Thursday.

"This is the difficult path we must follow if we are serious about change,” the Fifa president wrote in his weekly in-house magazine column.