A number of Swiss Banks are accused of involvement in a multi-billion-dollar corruption scandal at the Brazilian state-run oil giant Petrobras.
A Brazilian court has released documents alleging Swiss banks involvement in laundering funds which, the court said, were sourced illegally.
Brazil's Supreme Court minister Teori Zavascki has launched investigations into 47 politicians, including 12 senators and 22 deputies, accused of being part of a vast kickback scheme.
Swiss authorities said that they are cooperating with Brazilian prosecutors on the investigation.
Some of Brazil's top politicians -- including current and former senators, deputies, ministers, governors, and even a former president -- could now face prison sentences, if tried and convicted.
Under Brazilian law, only the supreme court can try senior politicians and cabinet members, as they have parliamentary privilege.
Prosecutors allege that construction and civil engineering companies signed falsely inflated contracts with Petróleo Brasileiro, and those operating the cartel misappropriated funds and funneled proceeds to politicians and parties, including the Workers' Party and its allies.
The exact scale of the alleged graft at Petrobras is not known, but one estimate puts it is as much as $30 billion.
As the country's biggest company, Petrobras has lost about $100 billion in value since September, putting pressure on the already sagging Brazilian economy and leading to Moody's credit rating agency to strip it of its investment grade -- with fears other agencies could follow suit.
By Betül Yürük and Benjamin Tavener