A New York couple who allegedly hacked a crypto platform, stealing billions in Bitcoin, are now pleading guilty to money laundering charges.

The couple — Ilya Lichtenstein and Heather Morgan — were arrested in February 2022 and charged in connection with the alleged hack of the Bitfinex platform and the theft of 120,000 Bitcoin.

At the time of their arrest, U.S. authorities recovered 95,000 of the stolen cryptocurrency, which was valued at US$3.6 billion. They have since recovered another US$475 million connected to the hack, the U.S. Department of Justice (DoJ) said.

According to U.S. authorities, “Lichtenstein used a number of advanced hacking tools and techniques to gain access to Bitfinex’s network” and then “fraudulently authorized more than 2,000 transactions” that resulted in 119,754 bitcoin being transferred to his crypto wallet.

“Following the hack, Lichtenstein enlisted the help of his wife, Morgan, in laundering the stolen funds,” the DoJ said.

The pair allegedly used fake identities, “darknet” markets, crypto mixing services, and other advanced techniques to try and conceal the ill-gotten gains.

They also converted a portion of the stolen assets into gold coins, “which Morgan then concealed by burying them,” the DoJ said.

The couple has each pleaded guilty to one count of conspiracy to commit money laundering, and Morgan pleaded guilty to one count of conspiracy to defraud the government.

The pair will be sentenced by a federal district court judge, and there will be a formal process for victims to make claims for any seized and forfeited property.