(The Hill) — An international group of law enforcement agencies seized a Hong Kong-registered cryptocurrency website and arrested its founder for allegedly operating a haven for criminals to launder funds.

Justice Department and Treasury Department officials on Wednesday alleged cryptocurrency exchange Bitzlato processed more than $700 million in illicit funds by failing to implement an effective anti-money laundering program and that it was aware some accounts were engaging in criminal activity.

Deputy Attorney General Lisa Monaco said U.S. and French authorities dismantled Bitzlato’s digital infrastructure and FBI agents arrested Russian national Anatoly Legkodymov, the founder and majority owner of the website, on Tuesday evening in Miami.

“Today, the Department of Justice has dealt a significant blow to the crypto crime ecosystem,” Monaco said.

Deputy Treasury Secretary Wally Adeyemo said the department’s Financial Crimes Enforcement Network designated Bitzlato as a “primary money laundering concern” after authorities identified nearly 50% of Bitzlato’s known transactions between 2019 and 2021 as involving illicit Russian finances or other “risky sources.”

“Bitzlato was particularly active in facilitating illicit activity, but it is ultimately part of a larger, larger ecosystem of cyber criminals that are allowed to operate with impunity within Russia,” said Adeyemo.

Bitzlato could not be reached for comment.

“This service has been seized by the Gendarmerie Nationale cyberspace command under the authority of the French Paris Prosecutor’s office (JUNALCO) as part of a coordinated international law enforcement action against Bitzlato,” reads a notice on Bitzlato’s website.

Much of the criminal complaint, which was unsealed in the Eastern District of New York on Wednesday, focuses on Bitzlato’s relationship with Hydra Marketplace, a massive Russian-based darknet market sanctioned by the U.S. last year.

The complaint claims a “substantial portion” of the billions in cryptocurrency Hydra received was sent directly from Bitzlato wallets.

It further alleges that Legkodymov and other senior managers were aware of the high volume of criminal funds and that the website had ineffective verification procedures.

Legkodymov resides in China but flew to New York in roughly October and continued to administer Bitzlato from the U.S., according to court filings. Officials declined to say at Wednesday’s news conference why he was in Miami at the time of his arrest.