Three Brazilian senators have formally sued President Jair Bolsonaro of malfeasance before the Supreme Court on Monday over allegations that he failed to initiate an investigation against a top ally over suspicions of massive corruption in the purchase of COVID-19 vaccines.

The opposition senators include Randolfe Rodrigues, the deputy chair of a commission investigating the administration’s pandemic response, which last week uncovered explosive accusations that Bolsonaro knew about suspected corruption in the deal for Indian-made Covaxin and failed to intervene.

A criminal case against Bolsonaro before the Supreme Court could see him removed from office, though Prosecutor General Augusto Aras, an ally, would have to bring charges.

A congressman close to Bolsonaro, Luis Miranda, testified that the president told him he suspected the scheme was the work of Ricardo Barros, a powerful congressman who is head of Bolsonaro’s coalition in the lower house.

Miranda said Bolsonaro told him in March he would order the police to investigate, but never did.