Prosecutors in Sao Paulo state have filed money laundering charges against former Brazilian President Luiz Inacio Lula da Silva, who is accused of hiding his alleged ownership of a seafront penthouse in the city of Guaruja.

Silva has denied he owns the apartment, which belongs to constructor OAS. OAS is one of the biggest targets of a separate corruption investigation that focuses on state-run oil giant Petrobras.

The charges filed Wednesday against Silva still need to be accepted by a judge.

In a statement, Silva said that investigators "are not unbiased." He still has not been heard by the state investigators in the case.

The decision comes days before an anti-government protest on Sunday, and five days after Silva was held for questioning and his home raided by the police.