FILE PHOTO: Spanish banker David Muino Suarez is escorted by federal police officers as he arrives to the Institute of Forensic Science in Curitiba, Brazil, November 28, 2017. REUTERS/Rodolfo Buhrer

BRASILIA (Reuters) - Federal prosecutors on Tuesday charged a Spanish-Swiss banker with laundering $21.7 million in graft money for Brazilian clients involved in the country’s largest corruption scandal, including jailed former lower house speaker Eduardo Cunha.

David Muino Suarez, a relationship manager of Zurich-based BSI bank, was arrested at Sao Paulo’s Guarulhos airport as he got off a flight from Switzerland on Nov. 27 and is being held in Curitiba, the centre of the so-called Car Wash investigation.

The federal prosecutors’ office in Curitiba said in a statement that Suarez, who has dual Swiss-Spanish nationality, knew the money came from bribes paid to Cunha and Pedro Bastos, a former executive at state-run oil company Petrobras, from an oil field acquisition in the African nation of Benin in 2011.

They said Suarez concealed the illegal financial operation with false information given to the bank’s compliance office.

It was not immediately known how the banker responded to the charges as his representatives could not be reached for comment.

Prosecutor Diogo Castor de Mattos said the almost four-year Car Wash probe had uncovered several cases of managers of international banks who helped Brazilian politicians, financial intermediaries and former Petrobras executives hide illegal money in offshore accounts.

Cunha is the highest profile politician convicted of graft and sentenced to 15 years in jail for his role in the corruption scheme, in which engineering companies paid billions of dollars in bribes and kickbacks from contracts with Petrobras and other state-run companies.