Prosecutors accused the younger Biden of lying about his use of narcotics when he purchased a Colt Cobra handgun in October 2018.
Bolsonaro, who has denied any wrongdoing, faces mounting legal jeopardy after losing his re-election bid, with many in Brazil believing he could soon end up in jail.
Trump was charged in an indictment in June with criminal counts, including violations of the Espionage Act, conspiracy to obstruct justice, and making false statements to investigators.
Trump is facing several different criminal prosecutions.
Trump, 77, already has entered uncharted territory as the first former U.S. president to face criminal charges.
17 individual studies have made the link between prenatal exposure to traces of lead and detrimental impacts on the brain lasting up to adulthood.