Criminal, cryptocurrency, money-laundering service ChipMixer has been shuttered following an international law enforcement effort led by the US Department of Justice (DoJ).

The cryptocurrency service for cybercriminals, according to charges, laundered more than $3 billion in illicit funds since 2017 for a roster of threat actors engaged in ransomware, fraud, and more. Minh Quốc Nguyễn (49) of Hanoi, Vietnam, is being charged with operating the illicit ChipMixer service, the DoJ added.

Cryptocurrency mixing involves using pools of cryptocurrency to make tracking electronic transactions almost impossible, so it’s perfect for money-laundering. It’s become a common service used by cybercriminals, especially as more governments regulate cryptocurrency exchanges.

“Today’s announcement demonstrates the FBI’s commitment to dismantling technical infrastructure that enables cybercriminals and nation-state actors to illegally launder cryptocurrency funds,” FBI Deputy Director Paul Abbate said in a statement about the ChipMixer takedown. “We will not allow cyber criminals to hide behind keyboards nor evade the consequences of their illegal actions.”