Brazil's Supreme Court named a long list of politicians under investigation over the multibillion-dollar graft case roiling state oil giant Petrobras, including the presidents of the senate and of the chamber of deputies.
On the list are 22 serving congressmen and 12 senators and it marks a new front in a snowballing scandal that has caused political and social uproar, threatening to tear apart the ruling coalition.
Not under investigation is President Dilma Rousseff, who was Petrobras board chair during much of the decade-long period when politicians allegedly benefited from huge kickbacks via inflated contracts struck between the oil firm and dozens of companies.
"Launching investigations was considered viable as there are indications of illegality," a court statement read, quoting a decision by Supreme Court presiding minister, Teori Zavascki.
Around three dozen politicians were named, many of them allies of the leftist Rousseff's ruling coalition, following a demand by public prosecutor Rodrigo Janot that the court lift their political immunity.
Those named are variously accused of crimes relating to involvement in a scheme facilitating corruption and money laundering which saw an estimated $3.8 billion creamed off inflated contracts over a decade.
Rousseff won re-election just four months ago, her top priority the revitalization of a flailing economy hamstrung by four straight years of low growth and rising inflation.
The naming of Congress president and senator Renan Calheiros and Eduardo Cunha, president of the chamber of deputies, could have severe repercussions for the centrist PMDB party and the ruling coalition.
The PMDB is the strongest political group in the senate and the second-biggest in the lower chamber after Rousseff's Workers' Party (PT).
Its support is therefore key in Congress for the PT.
Both Calheiros and Cunha have denied any wrongdoing, while Rousseff has denied all knowledge of the kickbacks scheme, backing the investigation.
The scandal, dubbed Operation Car Wash, broke a year ago when a former Petrobras director turned whistleblower in a bid to strike a plea bargain.
His accusations in evidence to investigators has little by little filtered through the media, suggesting that the kickback cash was destined for private accounts or to finance political parties.
Among those questioned but later released was PT treasurer Joao Vaccari Neto.