The Department of Justice worked with the Treasury Department and French law enforcement to seize many of Bitzlato’s resources, alleging the business facilitated illicit activity.

The United States Department of Justice announced a “major international cryptocurrency enforcement action” against crypto firm Bitzlato and the arrest of its founder Anatoly Legkodymov.

In a Jan. 18 announcement, U.S. Deputy Attorney General Lisa Monaco said authorities had taken enforcement actions against Bizlato in coordination with France, seizing Bitzlato’s website and labeling the business as a “primary money laundering concern” connected to Russian illicit finance. According to Monaco, the Department of Justice worked with the Treasury Department and French law enforcement to take action against Bitzlato for allegedly “conducting a money transmitting business that transported and transmitted illicit funds and that failed to meet U.S. regulatory safeguards.”

As part of the case against Bitzlato, FBI officials arrested Legkodymov, a Russian national based in China, on Jan. 17 in Miami. He is scheduled to be arraigned in the U.S. District Court for the Southern District of Florida.

U.S. authorities said the criminal complaint against Bitzlato was based on the firm being a “crucial financial resource” for the Hydra darknet marketplace, allowing users to launder funds including those from ransomware attacks:

“Hydra Market users exchanged more than $700 million in cryptocurrency with Bitzlato, either directly or through intermediaries, until Hydra Market was shuttered by U.S. and German law enforcement in April 2022. Bitzlato also received more than $15 million in ransomware proceeds.”

The enforcement action was a coordinated effort across Europe and the U.S. to seize many of Bitzlato’s resources — including the firm’s servers — as well as take the founder into custody. Monaco referred to the case as the “most significant enforcement effort” against an exchange since the National Cryptocurrency Enforcement Team was launched in October 2021.

Related: Cleaning up crypto: How much enforcement is too much?

Assistant Attorney General Kenneth Polite of the Department of Justice’s criminal division suggested U.S. authorities were “just getting started” in cracking down on similar firms involved in facilitating money laundering. Though no official directly commented on the ongoing case against crypto exchange FTX and its former CEO Sam Bankman-Fried, Monaco referenced crimes against the U.S. financial system “from a tropical island”.

This story is developing and will be updated.