Brazil's Federal Police on Friday arrested three former lower-house lawmakers and four other suspects in a new phase of the investigation into a massive bribery case centered on state-controlled oil giant Petrobras, officials said.

Andre Vargas, a member of the ruling Workers Party, or PT; Pedro Correa of the Progressive Party, or PP; and Luiz Argolo of the opposition Solidarity party were taken into custody, Fox News reported.

Correa was among those convicted in the so-called "trial of the century," another landmark Brazilian corruption case that was uncovered in 2005 and hit the administration of President Luiz Inacio Lula da Silva, mentor and predecessor of current head of state Dilma Rousseff.

Police also arrested Argolo's secretary, Elisa Santos; Vargas' brother, Leon Vargas; and two other individuals identified as Ivan Mernon da Silva Torres and Ricardo Hoffmann.

These seven most recent detainees are under investigation for criminal conspiracy, corruption, bid rigging, money laundering, influence trafficking, and use of false documents.

These arrests mark a new chapter in the massive corruption scandal that was brought to light last year and thus far has centered on Petrobras, although investigators say the case could extend to public bidding processes involving other state-run entities.

Petrobras, which accounts for 12 percent of Brazilian GDP, is under investigation following disclosure of widespread corruption said to have cost the company billions of dollars since the mid-1990s.