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By Associated Press

SAO PAULO -- State prosecutors have filed charges against former President Luiz Inácio Lula da Silva in a money laundering investigation, putting further scrutiny on one of Brazil's towering political figures who is being hounded by corruption allegations.

The charges brought by prosecutors in Sao Paulo state arise from allegations that he hid his ownership of a seafront penthouse in the city of Guaruja.

Former Brazilian President Luiz Inacio Lula da Silva (R) and Senate President Renan Calheiros talk after having a breakfast meeting at the latter's residence in Brasilia, on March 9, 2016.EVARISTO SA / AFP - Getty Images

Silva denies that he secretly owns the apartment, which belongs to construction company OAS. OAS is one of the main targets of a parallel federal corruption investigation that focuses on state-run oil giant Petrobras. Last week, Silva was held for questioning and his home raided in that probe.

The charges filed Wednesday against Silva still need to be accepted by a judge for the case to go forward. In a statement, Brazil's once-immensely popular ex-president said that the Sao Paulo state investigators "are not unbiased" and have no authority to conduct the investigation.

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The investigators have scheduled a press conference for Thursday.

Last Friday, federal investigators said they were looking into whether renovations at the Guaruja beachfront apartment and another project at a country house used by Silva and his family constituted favors in exchange for political benefit.

Both places have undergone major renovations paid for by construction companies that for decades have had contracts with the federal government. The companies are also at the center of the $2 billion Petrobras scandal.

Silva acknowledges having visited the penthouse twice, but says he never owned the apartment. He claims the country house belongs to friends who allowed him and his family to use it.

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Federal investigators are also trying to determine if Silva sold his influence in the current administration in exchange for speeches and donations to his nonprofit foundation Instituto Lula.

Jair Jaloreto, a Sao Paulo-based expert on money laundering, said the penthouse case that motivated Wednesday's charges is "very confusing indeed."

Brazil's former President Luiz Inacio Lula da Silva leaves a meeting with senators of the Brazilian Democratic Movement Party (PMDB) in Brasilia, Brazil March 9, 2016.ADRIANO MACHADO / Reuters

"I see more risk for Lula (Silva) in the investigations into the country house. If he didn't deliver the speeches he was paid for, that could also be money laundering. But this apartment case is difficult. He never used it, there is no document saying it was his. It will be tough for the investigators to prove," he said.

Silva governed from 2003 to 2010. Despite a votes-for-bribes scandal that took down his chief-of-staff and others, he left office with record high popularity levels and his hand-picked successor, current President Dilma Rousseff, handily won the presidency.

Silva and Rousseff have seen their popularity nosedive as Brazil has slipped into its worst recession in decades and the investigations have spread. Rousseff's approval ratings have dipped into single digits, though they've rebounded slightly of late. She faces impeachment proceedings.

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