SAO PAULO (Reuters) - Former Brazilian President Luiz Inacio Lula da Silva believes he will be exonerated of corruption charges by the country’s Supreme Court and promises to “fight until he wins,” according to an interview with the Folha de S.Paulo newspaper.

Former Brazilian President Luiz Inacio Lula da Silva attends the celebrations of the 38th anniversary of founding the Workers' Party in Sao Paulo, Brazil February 22, 2018. REUTERS/Paulo Whitaker

Lula, a popular leftist politician who was president from 2003 to 2011 and who plans to run in elections this year, repeated criticisms of prosecutors and judges who found him guilty of corruption in 2017 and upheld the verdict on a first appeal this year, which could bar him from running.

“So what do I expect? That the Supreme Court analyzes the process, looks at the testimony, the proof, and makes a decision. That’s why I believe I will be a candidate,” Lula said in the interview published on Thursday.

Lula, 72, is the most high profile of more than 100 people convicted in the “Cash Wash” investigation, the most sprawling of Brazil’s numerous corruption probes. He was found guilty of accepting a beachside apartment from an engineering firm vying for contracts at state oil company Petroleo Brasileiro SA, known as Petrobras.

A former union leader who remains popular due to rapid economic progress during his time in office, Lula criticized prosecutors for what his lawyers have called a reliance on the plea bargain testimony of one witness.

While Lula lost a first appeal in January, the Supreme Court may have the final say if they decide to hear any eventual appeal Lula’s lawyers make. Under Brazilian law, Lula will likely be barred from running in the October elections because his conviction has already been upheld.

In a January ruling, all three appellate court judges voted to uphold Lula’s convictions on taking bribes and money laundering. They also added 2-1/2 years to his sentence, condemning him to 12 years in prison. Lula so far remains free pending future appeals.

“I’m prepared. I’m calm,” Lula told Folha de S.Paulo, adding that he would not even consider supporting other candidates in the leftist Workers’ Party unless he were definitively barred from running.

“I’m certain that I will be absolved and that I will not be imprisoned.”

Lula, right-wing congressman Jair Bolsonaro, and environmentalist Marina Silva are leading the preliminary opinion polls ahead of October’s elections, which are also for members of Congress, governors, and state assemblymen.

(Corrects style of newspaper name in 1st and 8th paragraphs; notes in 2nd paragraph that Lula’s verdict has been upheld on a first appeal; clarifies in 6th paragraph that no appeal has been made yet to the Supreme Court)