An Odebrecht placard is pictured in front of a construction site in Rio de Janeiro, Brazil, June 19, 2015. Federal police agent Igor Romario confirmed that Odebrecht CEO Marcelo Odebrecht and Andrade Gutierrez CEO Otavio Marques Azevedo were among 12 people arrested on Friday in a corruption investigation at state-run oil firm Petrobras. Brazilian prosecutor Carlos Fernando dos Santos Lima said at a news conference in the southern city of Curitiba that an investigation into Brazil's two largest construction firms uncovered a sophisticated scheme of illegal acts, including participating in a cartel and fraud in project bidding. REUTERS/Pilar Olivares