The US Department of Justice (DoJ) has seized nearly US$3.6 billion (NZ$5.4 billion) related to the hack of Bitfinex in 2016 and accused a husband of wife of laundering the stolen cryptocurrency.
The DoJ said Heather Morgan and Ilya Lichtenstein were arrested over the alleged laundering of the proceeds of the missing 119,754 bitcoin, currently worth US$4.5 billion.
Bitfinex, a cryptocurrency exchange, was hacked with the perpetrator making more than 2000 unauthorised transactions. At the time of the hack, the price of bitcoin dipped by around 20 percent because of the theft.
While the DoJ didn't say the pair were responsible for the hack, it revealed the unauthorised transactions were sent to a wallet under Lichtenstein's control.
"Over the last five years, approximately 25,000 of those stolen bitcoin were transferred out of Lichtenstein's wallet via a complicated money laundering process that ended with some of the stolen funds being deposited into financial accounts controlled by Lichtenstein and Morgan," the DoJ said.
"The remainder of the stolen funds, comprising more than 94,000 bitcoin, remained in the wallet used to receive and store the illegal proceeds from the hack."
A court-authorised search warrant accessed online accounts controlled by the pair, and files belonging to Lichtenstein contained the private keys required to access the stolen funds, allowing the recovery of the majority of the stolen cryptocurrency.
According to reports, Lichtenstein is the founder of blockchain start-up Endpass, while Morgan is a published sales and marketing writer for Forbes and has released a rap video in which she calls herself the 'Crocodile of Wall Street'.
One of Morgan's Forbes articles is titled 'Protect your business from cybercriminals'.
The criminal complaint says the pair "employed numerous sophisticated laundering techniques", including fictitious identities, automated transactions and depositing the stolen money in darknet markets and then withdrawing the funds.
At other times money was spent on US$500 gift cards from Walmart, which were used to pay for purchases on Morgan's iPhone.
The charges Lichtenstein and Morgan face carry a maximum sentence of 20 years in prison.
"Criminals always leave tracks, and today's case is a reminder that the FBI has the tools to follow the digital trail, wherever it may lead," FBI deputy director Paul M Abbate. Said.
Acting executive associate director of Homeland Security Investigations Steve Francis said the action demonstrated the department's commitment to unravel technical fraud schemes, wherever they occurred.
