Police on both sides of the Atlantic have announced the arrest of 34 suspects in an operation against the laundering of Colombian drug money.
Authorities in the US, Colombia, Canada and the UK said they had broken a "massive" crime ring and seized millions of dollars.
Operation White Dollar focused for two years on an alleged conspiracy based in the Colombian capital Bogota.
If convicted, the suspects face a maximum sentence of 20 years in prison.
The alleged conspiracy involved the transfer of money earned from the sale of cocaine outside Colombia to people and companies inside the country.
It allowed Colombian firms and individuals to obtain US dollars without paying the taxes or transfer fees for which they would have been liable if they had bought the money legally.
The 34 people arrested are mostly the "brokers" who arrange for the drug proceeds to be wired to Colombians in return for Colombian pesos, the police forces said.
A US attorney in New York, David Kelley, said a prominent Colombian industrialist, Jose Douer-Ambar, had agreed to forfeit $20m acquired in such a way to the US, in return for a deferred prosecution.
The industrialist had purchased the $20m from the indicted peso brokers, the attorney said.
In addition, more than $1m has been frozen and seized from more than 20 separate bank accounts, including some in high street banks in Britain.
The British National Crime Squad said the laundering method, known as the "black market peso exchange", was very difficult to trace because most of the deals were done by word of mouth and there was no paper trail.
Because of these advantages, it said, it "has become one of the primary methods by which Colombian narcotics traffickers launder their illicit funds".