Brazilian Senator Flavio Bolsonaro, the leading right-wing challenger to President Luiz Inacio Lula da Silva in next month’s election, is under investigation for alleged corruption and money laundering tied to failed lender Banco Master, according to court documents unsealed on Friday.The probe into the senator, the eldest son of former President Jair Bolsonaro, was opened in July by Supreme Court Justice Andre Mendonca, a Bolsonaro appointee who has recently been hailed ‌as a hero by many on Brazil’s right, including Flavio Bolsonaro himself.The development could further shake an already volatile presidential race, with multiple opinion polls showing Flavio Bolsonaro and Lula statistically tied in a simulated second-round run-off.The judge opened the probe at the request of federal police as part of a broader investigation into the failed bank. But details of the investigation only became public after Chief Justice Edson Fachin ordered the proceedings related to the Banco Master case unsealed late on Thursday.Mendonca complied with Fachin’s request, releasing thousands of pages of court records.A combination photo shows Brazil’s President Luiz Inacio Lula da Silva (left) and presidential candidate and Senator Flavio Bolsonaro. Photo: ReutersFurther details and the broader implications of the newly unsealed documents were not immediately clear, as parts of the case, including details of ⁠the investigation into Senator Bolsonaro, remained under secrecy as police actively investigate.