US prosecutors have charged four people with ties to the law firm at the centre of the massive leak of offshore financial data known as the "Panama Papers".
The four are charged with taking part in a decades-long scheme to evade US taxes.
Three of the four people have already been arrested, the US Department of Justice said.
Harald Joachim von der Goltz, a client of the Panamanian law firm Mossack Fonseca & Co, was arrested in London on Monday.
Dirk Brauer, an employee of an asset management company closely tied to the firm, was arrested in Paris on 15 November.
Richard Gaffey, a US-based accountant, was arrested in Massachusetts on Tuesday, according to prosecutors.
Prosecutors said the fourth defendant, Ramses Owens, was a lawyer at Mossack Fonseca & Co and remains at large.
The law firm shut down earlier this year.
The most serious charges in the case, which include wire fraud and money laundering conspiracy, carry a maximum sentence of 20 years in prison.
The "Panama Papers" scandal broke in 2016 when a leak of 11.5 million files from Mossack Fonseca's digital archive revealed how wealthy and influential figures across the world had created offshore businesses to safeguard assets.
The information was obtained by German newspaper Sueddeutsche Zeitung, which shared it with the International Consortium of Investigative Journalists.