Former Brazilian President Luiz Inacio Lula da Silva has been detained as part of a huge fraud inquiry into the state oil company Petrobras.
The former president’s house was raided by federal police agents and he was brought in for questioning.
Lula, who left office in 2011, has denied allegations of corruption.
The long-running inquiry, known as Operation Car Wash, is probing accusations of corruption and money laundering at Petrobras.
Dozens of executives and politicians have been arrested or are under investigation on suspicion of overcharging contracts with Petrobras and using part of the money to pay for bribes and electoral campaigns.
Police said they had evidence that Lula, 70, received illicit benefits from the kickback scheme.
Lula’s institute said in a statement the “violence” against the former president was “arbitrary, illegal and unjustifiable”, as he had been co-operating with the investigations.