Swiss banks have reported suspicions of money laundering by soccer’s governing body FIFA.
Local prosecutors are investigating 53 cases of possible money laundering in their inquiry into bidding for the 2018 and 2022 FIFA World Cups.
Swiss Attorney General Michael Lauber said the incidents had been reported by Swiss banks.
He said his office was analyzing a “huge amount” of seized FIFA data in its inquiry.
The Swiss investigation is running in parallel to one being carried out by the US.
The 2018 and 2022 World Cups were awarded to Russia and Qatar respectively. But leading FIFA official Domenico Scala has said the awards could be cancelled if evidence emerges of bribery.
Russia and Qatar deny any wrongdoing.
The seven were held at the request of the US DoJ which has charged 14 current and former FIFA officials and associates on charges of “rampant, systemic, and deep-rooted” corruption.
The charges follow a three-year inquiry by the FBI.
Also in May, Swiss prosecutors opened separate criminal proceedings “against persons unknown on suspicion of criminal mismanagement and of money laundering” in connection with the 2018 and 2022 World Cups.
However, until now, much less has been revealed about the Swiss investigation than the inquiry being led by the FBI.
Michael Lauber told a news conference that the investigation was “huge and complex on many levels” and would take a long time.
“We note positively that banks in Switzerland did fulfill their duties to file suspicious activity reports. Partly in addition to 104 banking relations already known to the authorities, banks announced 53 suspicious banking relations via the anti-money-laundering framework of Switzerland,” he said.
Michael Lauber said he did not rule out interviews with FIFA president Sepp Blatter as part of his investigation.
Sepp Blatter has denied any wrongdoing and announced earlier this month that he will resign.
The attorney said his investigation was separate from that being carried out by the FBI and that documents and data would not be shared automatically with the US.
Michael Lauber added: “The world of football needs to be patient. By its nature, this investigation will take more than the legendary 90 minutes.”