A Brazilian supreme court judge on Monday ordered a probe into accusations by former justice and security minister Sergio Moro that President Jair Bolsonaro sought to "interfere" with police investigations.
In his decision, Judge Celso de Mello gave the federal police 60 days to question Mr Moro about his explosive allegations against the right-wing president.
The findings, which will be handed over to the attorney general, could result in either a request for a political trial against Mr Bolsonaro or an indictment against Moro for false testimony.
According to the judge, the alleged crimes seem to have "an intimate connection with the exercise of the presidential mandate," thus allowing for an investigation of the leader.
Moro, a former anti-corruption judge, resigned on Friday after clashing with Mr Bolsonaro over the sacking of the federal police chief, accusing the president of political interference.
The judge's document lists seven accusations against Mr Bolsonaro, including malfeasance and obstruction of justice.
Should the investigation confirm the allegations, it will be up to the lower house of the National Congress to initiate impeachment proceedings against Mr Bolsonaro and potentially remove him from office.
In 2017, the prosecutor general's office asked to open two investigations against then-president Michel Temer, and in both cases the request was rejected by the Chamber of Deputies.
The tensions come at the height of the global coronavirus crisis.
Mr Bolsonaro has repeatedly downplayed the danger of Covid-19 and earlier this month fired his health minister, Luiz Henrique Mandetta, who supported isolation as a tool to contain the spread of the pandemic.
A poll published Monday night shows divided opinions about Mr Bolsonaro's future, with 45 per cent of Brazilians saying Congress should open an impeachment process against him.
In comparison, 48 per cent think Mr Bolsonaro should not be impeached, according to the Datafolha poll, which ran in the Folha de S. Paulo daily.
Behind the scenes, changing the head of the federal police, an investigative body that reports to the justice ministry, is seen as an attempt by Mr Bolsonaro to control investigations that surround his family and political allies.
One probe, opened in March 2019, is investigating false news campaigns to threaten or slander supreme court judges who opposed Mr Bolsonaro's projects, such as liberalising the carrying of arms.
Another, initiated by the attorney general last week, is investigating a demonstration outside the army headquarters in Brasilia by Mr Bolsonaro supporters who called for military intervention in handling the coronavirus pandemic while protesting against stay-at-home orders.
Mr Bolsonaro, a former army captain who has been criticised for previously praising Brazil's brutal 1964-85 military dictatorship, also attended the protest.
Moro, who made his name leading the corruption investigation that saw former leftist president Luiz Inacio Lula da Silva jailed for accepting a bribe, resigned after Mr Bolsonaro dismissed the federal police chief, who was a close ally of the minister.
"The change at the head of the federal police without a genuine reason is political interference that harms my credibility and that of the government," Mr Moro said Friday.
Mr Moro said Mr Bolsonaro had told him he was replacing the federal police chief for someone with whom he had "personal contact, whom he could call, ask for information, intelligence reports."
"Providing this type of information is not the job of the federal police," Moro said, insisting on independence for investigations.
That night, he presented on television a WhatsApp exchange with Mr Bolsonaro in which the president appears to exert pressure for the replacement of the federal police chief.
According to Brazilian media, the former judge has recordings of discussions with the president.
Mr Bolsonaro hit back at Mr Moro, accusing him of being motivated by "ego" and making "unfounded accusations."