RIO DE JANEIRO, July 5 (Reuters) - Brazilian President Jair Bolsonaro was involved in a scheme to skim salaries of his aides while a federal deputy, website UOL reported on Monday, citing what it said were audios of his former sister-in-law explaining his role in the alleged racket. The scheme, known locally as rachadinha, involves hiring close associates as employees and then receiving a cut of their public salaries back from them. Rio de Janeiro state prosecutors have formally pressed charges against federal Senator Flavio Bolsonaro, the president"s eldest son, over his alleged participation in a similar racket when he was a state lawmaker. The UOL story, based on audio recordings of Bolsonaro"s former sister-in-law, Andrea Siqueira Valle, provided by a source, is the first time the president has been directly implicated in a rachadinha scheme, despite numerous awkward questions about his role in Flavio Bolsonaro"s alleged racket in Rio. This comes as Bolsonaro is seeing his anti-graft credentials, which helped get him elected president in 2018, questioned by a simmering scandal over alleged corruption in the government"s vaccine procurement efforts. Senator Renan Calheiros, sponsor of a Senate inquiry into the government"s handling of the pandemic, said on Monday that Siqueira Valle could be called before the committee for questioning. While the rachadinha is not directly connected to the Senate inquiry, it adds to recent allegations about irregularities in the government"s purchase of vaccines and calls into question Bolsonaro"s anti-corruption platform. The president"s office declined to comment. A lawyer representing Bolsonaro contacted by UOL denied illegalities. In one audio recording, Andrea Siqueira Valle explains that her brother, Andre Siqueira, who was also on Bolsonaro"s payroll, was fired for refusing to hand back the agreed amount to the now-president. "André had a lot of trouble because he never returned the right money that had to be returned," she says on the recording. "Eventually, Jair said ... "Enough. You can get rid of him because he never gives me the right amount of money."" Reuters was unable to confirm the legitimacy of the recordings or the information in the story. Andrea Siqueira Valle declined to comment to UOL. UOL also reported that on two separate occasions, Siqueira Valle told people close to her about the racket allegedly being run from Bolsonaro"s office. The accusations against Bolsonaro for allegedly misusing public funds as a federal lawmaker could open him up to a federal probe. However, Brazilian law does not allow a sitting president to be charged for any crime committed before taking power. Instead, prosecutors would need to wait until the president has left office to bring charges.