The Swiss Federal Prosecutor’s Office has broadened its investigation into alleged money laundering connected to the World Cup bids by Russia and Qatar.

The number of suspicious transactions has now risen from 53 to 81.

The investigation began in May when prosecutors seized data and documents from Fifa headquarters in Zurich. World football’s governing body had initiated the probe by bringing a complaint to the prosecutor’s office.

Coincidentally, on the same day, May 27, police arrested seven football officials in connection with a separate criminal probe in the United States. Six of the seven remain in jail in Switzerland while extradition proceedings run their course, while the 7th has agreed to be extradited to the US.

The Swiss investigation centres on claims that the bidding process for the 2018 and 2022 World Cup tournaments, which were won respectively by Russia and Qatar, was influenced by bribes paid to delegates.

On June 17, Swiss public prosecutor Michael Lauber said that banks had alerted his office to 53 suspicious transactions. But on Monday it was confirmed that the number had now increased to 81.

Last month, Lauber told the media that the investigation could take months or even years to complete.

“The world of football must be patient. It will take more than the legendary 90 minutes. It could be months or years,” he said.