André Esteves, the CEO and controlling shareholder of BTG Pactual SA, was arrested at his home in Rio de Janeiro. Documents were seized from his home and the bank’s headquarters in São Paulo, said a source, who requested anonymity because of the sensitivity of the issue.

In Brasilia, the police also arrested ruling Workers’ Party senator Delcidio Amaral, a veteran lawmaker who is close to former president Luiz Inacio Lula da Silva. Chairman of the Senate’s economic affairs committee, Amaral is a key figure in pushing through fiscal austerity measures sent to Congress by President Dilma Rousseff’s government.

Brazil’s Supreme Court authorized the arrests after prosecutors presented evidence they had interfered with the investigation into kickbacks and bribes paid from contracts with Petroleo Brasileiro SA, as the company is know, a court spokesperson said.

Police entered the Brazilian Congress to search for documents in connection with Amaral’s arrest. His chief of staff and his lawyer were also arrested, a police source said.

Esteves’ arrest was made on a temporary basis, the first source said, without elaborating. The bank confirmed the arrest.

Esteves, a 47-year-old billionaire, has steered BTG Pactual through turbulent times in Brazilian capital markets as the economy plunged into its worst recession in a quarter of a century. In recent years he has also ramped up bets in riskier investments such as U.S. mortgages, global credit and emerging market assets.

He is worth about $2.2 billion, according to Forbes Magazine. BTG Pactual is Brazil’s sixth largest bank and the largest independent investment bank in Latin America.

BTG Pactual units fell around 19 percent in early trading on the Sao Paulo stock exchange as a sweeping probe of corruption stemming from state-run oil company Petrobras threatened to ensnare the country’s biggest investment bank.