The investigation into arguably the biggest corruption scandal in Brazil involving state-owned oil company, Petrobrass, has claimed its first set of victims, with a former treasure of the country’s ruling Workers party sentenced to more than 15 years in jail for collecting bribes of more than $1 million.

Joao Vaccari was sentenced for collecting kickbacks disguised as campaign donations from Toyo Setal, an oil company contracted by Petrobrass between 2008 and 2012.

Also jailed was Renato Duque, Petrobras’ former head of corporate service, who was for more than 20 years for accepting at least $9 million for helping construction and engineering get inflated contracts from Petrobras.

According to the federal judge who delivered the ruling, Sergio Moro, Duque, also served as conduit for Vaccari.

While the two men remain in prison, they can appeal their sentences.

President Dilma Rousseff has seen her ratings crash badly following the scandal, which has been blamed for the country’s slide into recession. She was chair of Petrobras’ board when the sleaze was allegedly carried out, and while she has not been indicted, she continues to maintain her innocence.

According to prosecutors, more than $2 billion exchanged hands illegally for more than 10 years. This money allegedly was paid to top executives of the state-run company by wealthy construction companies seeking to win lucrative and inflate contracts.

In June, Marcelo Odebrecht, the head of Odebrecht SA, Latin America’s biggest engineering and construction company, with presence in 21 countries, including in Africa, was arrested alongside Otavio Marques, the head of Brazil’s second-biggest construction company, Andrade Guitierrez, and 10 other.

Also under investigation are more than 50 congressmen and other top government officials.