Brazilian federal prosecutors this week filed charges against the strategist behind President Dilma Rousseff’s successful electoral campaigns in 2010 and 2014.

João Santana and his wife and partner in their consulting firm, Mônica Moura, were charged with corruption, conspiracy and money laundering. Prosecutors accused the couple of receiving $7.5 million in payments that were diverted from state-owned oil giant Petrobras into Santana’s bank accounts outside Brazil, the Wall Street Journal reported.

The charges are part of the far-reaching criminal investigation known as "Lava Joto," or Operation Car Wash, which involves a multimillion-dollar kickback scheme at Petrobras. The two-year inquiry has involved scores of politicians and business leaders, led to over a hundred search and seizure operations and resulted in a handful of imprisonments, according to Brazil’s Federal Prosecution Service.

Santana and Moura, who have previously denied any wrongdoing, declined to comment on the latest charges, the Journal reported. The couple has been held in custody since late February. They also helped Rousseff’s predecessor Luiz Inácio Lula da Silva win re-election in 2006.

Rousseff hasn’t been implicated in the Petrobras scandal. But she is facing calls for her ouster amid allegations that she used money from giant public banks to cover budget shortfalls. Brazil’s Senate could hold an impeachment trial in May; if senators consider the motion, the president will be forced to step aside for 180 days and could be forced out permanently.

Still, Rousseff’s exit would hardly end scandals in the highest office. The three men in line to replace Rousseff if she is impeached are themselves under investigation in the Petrobras case and other operations.

Chamber of Deputies Speaker Eduardo Cunha, who is second in line for the presidency and spearheaded the campaign to oust Rousseff, was accused Friday of receiving a bribe worth 52 million reais ($15 million), the Brazilian Folha de S. Paulo reported.

Along with Santana and Moura, federal prosecutors this week filed new charges against Marcelo Odebrecht, the former boss of construction giant Odebrecht SA, for money laundering. According to the charges, while Odebrecht was heading the company, he set up a unit devoted to the payment of bribes to win contracts with Petrobras.

A Brazilian judge earlier this year sentenced Odebrecht to nearly two decades in prison on separate charges for his involvement in the Petrobras scandal. The construction magnate has denied any wrongdoing.

The company Odebrecht SA is also involved in the car wash corruption investigation relating to two projects build ahead of the 2016 Summer Olympic Games in Rio de Janeiro. A subway line and an urban renewal project in a downtown port area — both multibillion-dollar ventures — were cited in a list of projects that may have received illicit funds from executives at Odebrecht SA, according to court documents cited by Bloomberg.