RIO DE JANEIRO (Reuters) - Brazilian investigators conducted one of their largest operations against graft ever on Thursday, targeting a money laundering ring linked to powerful politicians and businessmen that moved $1 billion through offshore accounts in 52 countries.

Federal prosecutors in Rio de Janeiro said that arrest warrants were issued for 53 people, nearly all of them black-market money changers. The information on illicit transactions for major companies and politicians those suspects have is certain to be “explosive,” one prosecutor said.

Authorities noted at a news conference that the “Car Wash” corruption investigation that began in 2014 and has morphed into one of the world’s largest anti-graft efforts began with the arrest of a single money changer.

“This sting opens the door on an unknown universe,” said prosecutor Rodrigo Timoteo. “We have pulled back the first layer, but there are many more.”

Investigators were able to conduct Thursday’s raids and arrests because of plea-bargain testimony of two money changers, Vinicius Claret and Claudio Barbosa, who moved illegal money for former Rio de Janeiro governor Sergio Cabral, who is serving over 100 years on several corruption convictions.

Two of the money changers arrested on Thursday in Uruguay, identified by prosecutors as Francisco Munoz and Raul Pegazzano, had allegedly carried out illegal operations in the past for the world’s largest meatpacker, JBS SA.

The company said in a statement that its executives who reached plea deals with prosecutors had already given detailed information about the company’s connection with the two me.

Prosecutors said they have asked a court to order the confiscation of 7.5 billion reais ($2.13 billion) in cash and goods from those linked to the laundering ring, half of that to pay to the government the amount of money illegally moved over the past two decades and half to pay fines.