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Brazil's Supreme Court will investigate the speakers of both houses of Congress and more than two dozen other politicians in connection with a multibillion-dollar kickback scheme at state-controlled oil company Petrobras.
The scandal has shaken the political establishment and undermined support for President Dilma Rousseff, who was narrowly re-elected last year and is struggling to stave off an economic recession and a downgrade by credit rating agencies.
A court official said on Friday that 54 people were under investigation, including senators and congressmen, all but one from Rousseff's governing coalition.
Heading the list are the president of the Senate, Renan Calheiros, and the Speaker of the Chamber of Deputies, Eduardo Cunha, both of the PMDB, Brazil's largest party and Rousseff's main coalition ally.
Two members of Rousseff's cabinet during her first term are under investigation: Senator Gleisi Hoffmann, who was her chief of staff, and former mines and energy minister Edison Lobao.
Only one opposition politician, Senator Antonio Anastasia, of the PSDB party, will be investigated.
Under Brazilian law, elected politicians can only be tried by the highest court, which must now decide with the help of prosecutors whether there is enough proof to put them on trial.
