An explosive new twist in Brazil's corruption and impeachment crisis has weakened President Dilma Rousseff days before her probable suspension from office and strengthened the man likely to replace her.
The probe into a vast corruption network centered on state oil giant Petrobras has already sucked in dozens of figures from the country's political and business elite.
But leaked documents suggest the scandal is now closing in rapidly on Rousseff and ex-president Luiz Inacio Lula da Silva -- Rousseff's main political ally and the unofficial leader of Brazil's left.
A request by chief prosecutor Rodrigo Janot for the Supreme Court to authorize an investigation into Rousseff, Lula and other close allies of the president was reported late Tuesday in Brazilian media but had yet to be confirmed by officials.
The development came a week before the Senate is due to vote on opening an impeachment trial against Rousseff on unrelated charges. If, as expected, the Senate goes ahead, she will be suspended for six months -- and many analysts believe she has few chances of ever returning to office.
The rapporteur for the Senate committee that will make a recommendation to the full chamber on Friday said Wednesday that he backed "the installment of the impeachment process."
Janot's leaked request for the corruption probe names 31 politicians and other figures, also including opponents of Rousseff, illustrating how the Petrobras embezzlement and bribery scheme allegedly spread throughout the ruling class.
But one name is conspicuously absent: Vice President Michel Temer, who will take over from Rousseff, his bitter opponent, if she is suspended next week.
Although Temer has also been named previously as being linked to the sprawling embezzlement ring, the evidence "does not merit requesting the opening of an investigation into him," a source at the prosecutor's office, who asked not to be identified, told AFP.
At the heart of Brazil's ever-escalating political meltdown is the Petrobras scheme that ran for years, mostly under the 2003-2010 presidency of Lula.
Politicians, lobbyists and outside executives conspired with Petrobras leaders to rob the oil company through inflated contracts. Bribes oiled the system and some of the money was used to finance election campaigns both for Rousseff and Lula's Workers' Party and for the center-right opposition.
Dozens of people have already been charged, prosecuted or imprisoned, including some of the country's richest men and leaders of all political stripes in Congress.
Rousseff has not been named in any direct corruption charges, although she was chairman of Petrobras during much of the time the scheme was underway.
However, according to reports in Globo, Folha de Sao Paulo and Estadao dailies, Janot wants to investigate her and Lula for allegedly trying to obstruct the main Petrobras probe headed by Judge Sergio Moro.
The charge rests principally on Rousseff's attempt in March to bring Lula into her cabinet. She said Lula would help her fight off impeachment, but Moro accused her of seeking ministerial immunity for the ex-president to help him dodge existing money laundering charges also connected to the Petrobras scam.
High-ranking politicians in Brazil can only be judged at the Supreme Court, meaning they are not directly under the jurisdiction of the crusading Moro and, in many cases, are able to spin the legal process out.
When Moro controversially published a secret wiretap recording of a phone conversation between the two leftist leaders that appeared to support his claims, the Supreme Court froze Lula's appointment.
Janot is also reported to be probing Lula with a separate obstruction of justice accusation -- that he tried to pay off jailed senior Petrobras director Nestor Cervero not to testify about the scheme.
And the leaked Janot documents appeared to signal that Lula is being targeted on an even bigger scale.
Janot was quoted as saying by the Folha newspaper that the vast Petrobras scheme "could never have functioned for so many years and in such a broad and aggressive form under the federal government without participation of ex-president Luiz Inacio Lula da Silva."
Rousseff lashed out Wednesday at a former ally, Senator Delcidio do Amaral, who is also accused in the Petrobras affair and has turned state's witness, feeding Janot with evidence against his old Workers' Party colleagues.
Rousseff called his testimony "absolutely lacking substance and above all lies." She also attacked the leaking of sealed court documents "on the eve" of her impeachment vote.
The impeachment case rests on accusations in Congress that Rousseff illegally manipulated government budget accounts, a relatively technical issue that is not tied to the Petrobras issue and which she says has been politicized in order to mount a "coup" against her.
The Senate will vote on May 12 whether to open the impeachment trial.
Benefiting from the latest turmoil is Rousseff's vice-president-turned-enemy, Temer. He could become acting president before the end of next week and has been busily discussing his plans for new ministers and how to address Brazil's ruinous recession.
But the fact that he was not included on Janot's long, leaked list of politicians surprised some, given that Temer has been on the radar of the corruption probe.
Amaral told prosecutors that Temer was involved in the Petrobras scheme, with links to two executives there who are now in prison.