Former Brazilian president Luiz Inacio Lula da Silva was "fully aware" of a vast bribery network at Petrobras and even directed the corruption scheme, a former director at the state oil company said.
Lula, a leftwing leader who was in office from 2003 to 2010, and his lawyer denied the accusation Friday by Renato Duque, a former director of services at Petrobras.
Duque told judge Sergio Moro that he met Lula at least three times in 2012, 2013 and 2014, in a statement broadcast by major media outlets.
"On these three occasions, it was clear, very clear to me, that he (Lula) was fully aware of everything and that he was in charge" of the bribery network at Petrobras, said Duque, who is serving a prison term of more than 50 years for bribery and money laundering.
A lawyer for the former president, Cristiano Zanin Martins, called it an attempt to "negotiate future benefits in exchange for frivolous accusations."
Lula is scheduled to appear Wednesday in front of Moro, who is carrying out the "Car Wash" investigation into embezzlement and bribery at the highest levels of Brazilian politics.
For years, contractors like the Odebrecht construction conglomerate paid bribes to top politicians and parties to get business deals. At the center of the scheme, the politicians and Odebrecht conspired in a pay-to-play scheme at state oil company Petrobras.
Lula's upcoming court appearance centers around a luxury apartment that he allegedly received from construction company OAS in exchange for illegal favors.
Prosecutors have previously called Lula the "top commander" in the corruption scandal, which is also being investigated by the Supreme Court. In total, he is facing five separate trials linked to Car Wash allegations.
Despite his mounting legal problems, and speculation over whether he will end up being convicted and jailed, polls show that Lula remains Brazil's most popular politician. He is the frontrunner in polls for the 2018 presidential elections.
He said in a speech to his Workers' Party on Friday that "if they do not arrest me soon, who knows if one day I can make them stop telling lies."