The 45-year-old senator had been polling neck-and-neck with 80-year-old President Luiz Inacio Lula da Silva, who is expected to seek a fourth term in presidential elections in October.
But a change may be underway following the publication of an audio recording by investigative outlet The Intercept, in which Bolsonaro asked disgraced banker Daniel Vorcaro to finance a film he was making about his father, former far-right president Jair Bolsonaro.
Polls had projected a Bolsonaro-Lula tie in the second round, giving a slight advantage to the right-wing hopeful.
Now, his ratings appear to have dwindled, with one poll putting the right-wing candidate seven points behind leftist Lula.
Vorcaro was the major shareholder in the small private Master Bank that collapsed last year, sparking a major fraud investigation that has rattled the highest echelons of power in Latin America’s largest economy.
According to The Intercept, the contentious audio is part of a series of records documenting a deal in which Vorcaro pledged to contribute US$24 million to the film “Dark Horse”, in which “The Passion of the Christ” star Jim Caviezel plays Jair Bolsonaro.
“It makes me uncomfortable to be asking you,” Flavio Bolsonaro tells the banker in the recording, calling him “brother.”
“We’re at a very decisive moment here with the film. And since there are many overdue payments, everyone is tense,” he says.
Just under half of that amount was actually paid, the publication said.
Bolsonaro said that “zero public funds” were involved in the transaction.
Unfazed
Bolsonaro is at the helm of the right-wing movement once steered by his father, who is in jail for an attempted coup.
The senator told his party members Tuesday he felt “very calm” as the published recording threatened to dent his public support.
He did admit, however, that he had met with Vorcaro when the banker was under house arrest.
Nevertheless, his political supporters show no sign of bolting.
“There is no discussion whatsoever about the hypothesis of replacing Flavio” as a party candidate, pro-Bolsonaro lawmaker Evair de Melo told AFP.
The left, meanwhile, has seized the opportunity to gain ground.
Ivan Valente, a member of the leftist party PSOL which is allied with Lula’s Worker’s Party, called the scandal “perhaps the most important development” of the pre-campaign.
“If the revelations continue, it will be lethal for Bolsonaro’s candidacy,” he told AFP, adding Lula may be able to curry favour among “disappointed” conservative voters.
‘Bolsonaro blood’
The recording had left Bolsonaro “a very weakened candidate”, Marcio Coimbra, director of the think tank Casa Politica, told AFP.
Despite the “wear and tear”, however, Bolsonaro senior will ensure his son’s candidacy “until the end”, according to Coimbra.
The former president endorsed his son over other more viable candidates as a way to “keep the right under his control” – and for that it was “necessary to have Bolsonaro blood”, he said.
The younger Bolsonaro has sought to portray himself as a more moderate politician than his father, although on issues such as security he has pledged to follow the hardline approach of El Salvador’s Nayib Bukele.
Jair Bolsonaro “will always be my guiding star. He is my compass, my point of reference,” Flavio Bolsonaro told CNN Brasil.
The convicted ex-president’s son has also had run-ins with the justice system.
In 2020, the public prosecutor accused him of embezzling public funds when he was a state deputy in Rio de Janeiro, but the investigation was closed without charges.