Petrobras may have overpaid as much as 1.2 billion dollars in transactions being investigated for potential kickbacks, Brazil's national accounting office said Tuesday.
The alleged graft issue at the state oil giant and elsewhere was used against President Dilma Rousseff in her reelection campaign but did not stop her from winning -- while promising she would fight corruption harder.
Voters did not blame Rousseff -- who was on Petrobras' board at the time -- in two rounds of voting in which she prevailed last month.
"We have demonstrated that there was overbilling (at the) Pasadena (refinery). And we found evidence this happened with other major projects, all of which were worth a total of almost 1.2 billion dollars," said Augusto Nardes, head of the government's accounting arm, known as the TCU.
The Pasadena refinery case alone cost Petrobras 317 million dollars, Nardes said.
With Rousseff board chair at the time, Petrobras in 2006 approved the purchase of a 50 percent stake in the Pasadena facility from Belgian firm Astra Oil in a $370 million deal.
Astra had only a year earlier bought the entire site for $42 million.
In 2008, Petrobras ended up having to buy the other 50 percent after losing a legal battle.
As part of a plea bargain bid to reduce a potential 40-year jail term, Paulo Roberto Costa, a former Petrobras chief, told police about what he claims was a massive system of kickbacks benefiting some 50 politicians, most belonging to Rousseff's Workers Party and coalition allies.
The accused have denied the allegations.