Swiss police on Wednesday raided HSBC's offices in Geneva following an inquiry into the bank's alleged money laundering practices.

A statement from the prosecutor's office reportedly said: "Following the recent revelations related to the HSBC Private Bank (Switzerland), the public prosecutor announces the opening of a criminal procedure against the bank.”

Prosecutors, who are looking into illegal tax activity at the bank, reportedly added that they could expand the inquiry “to include physical persons suspected of committing or participating in acts of money laundering.”

Nobody at the bank was expecting the raid, according to a report by The Financial Times, which cited unnamed sources. The bank had earlier released a statement saying it would cooperate with authorities.

Last week, HSBC had admitted that its Swiss branch may have held accounts that helped clients dodge taxes, after a report detailing these practices was published by the International Consortium of Investigative Journalists (ICIJ). The bank said that it is “accountable for past control failures” and is currently facing criminal investigation in the U.S., France, Belgium and Argentina.

Swiss prosecutors said the investigation comes in the wake of the leaked documents, which allegedly show that HSBC's Swiss branch helped clients withdraw “bricks” of cash and conceal their transactions from authorities around the world, The Guardian reported.

A former HSBC employee, Herve Falciani, leaked the data to French tax authorities in 2008, following which France shared it with governments around the world. The data was then acquired by French publication Le Monde and the ICIJ, which analyzed and published it, CBC reported.