Police said Monday that Antonio Palocci was detained in Sao Paulo. A statement alleges he maintained a "criminal relationship" with officials at Brazilian constructor Odebrecht.
The company was a principal participant in a kickback scheme at Petrobras that authorities say resulted in more than USD 2 billion in bribes over more than a decade.
Palocci was finance minister and then chief of staff during much of Silva's 2003-2010 government. He is alleged to have negotiated deals on behalf of Silva's Workers' Party. Lawyer Jose Roberto Batochio says Palocci is innocent and calls the arrest a "spectacle.