Tornado Cash developers Roman Storm and Roman Semenov were arrested and charged with money laundering and sanctions violations tied to their work with the privacy mixer which “facilitated more than $1 billion in money laundering” for North Korea’s Lazarus Group.

The mixer, which obfuscates the origin of funds transacted through it, was sanctioned last year by the U.S. Treasury Department’s Office of Foreign Asset Control (OFAC) after allegations that Lazarus had laundered the funds from multiple crypto hacks through it. OFAC sanctioned Semenov as well on Wednesday.

In a statement, U.S. Attorney Damien Williams said Tornado Cash and its operators “knowingly facilitated” money laundering.

“While publicly claiming to offer a technically sophisticated privacy service, Storm and Semenov in fact knew that they were helping hackers and fraudsters conceal the fruits of their crimes. Today’s indictment is a reminder that money laundering through cryptocurrency transactions violates the law, and those who engage in such laundering will face prosecution,” he said.

“Tornado Cash has been used to launder funds for criminal actors since its creation in 2019, including to obfuscate hundreds of millions of dollars in virtual currency stolen by Lazarus Group hackers,” a Treasury press release said.

This is a developing story and will be updated.