Exclusive: Middleman implicates top executives at Vitol, Trafigura in alleged bribery ring

A middleman in a graft scheme at Brazilian state oil company Petrobras has implicated the chairman of global energy trading firm Vitol in a bribery operation to obtain oil contracts, as well as two high-ranking executives at rival Trafigura and its former CEO, according to plea bargain testimony seen by Reuters.