The Bitfinex hack in 2016 ended with hackers stealing 119,754 Bitcoin.
The US government has seized over 94,000 BTC worth $3.6 billion, with two individuals arrested in connection to the hack.
The US Justice Department has seized Bitcoin worth $3.6 billion in an operation tied to investigations into the 2016 hack on cryptocurrency exchange Bitfinex.
The agency also announced that two individuals had been arrested for their connection to the theft.
According to a statement from the Justice Department, Ilya Lichtenstein and Heather Morgan will be arraigned on Tuesday afternoon for conspiracy to launder cryptocurrency and fraud. Both were arrested in New York following "meticulous work" by US law enforcement agents.
Lichtenstein and Morgan allegedly stole 119,754 Bitcoin in over 200 transactions following the breach and managed to launder 25,000 BTC in the last five years.
The DOJ said that over 94,000 BTC never moved from "a wallet used to receive and store the illegal proceeds from the hack."
Investigators accessed the wallet on 31 January and on 1 February, executed a lawful seizure. A US court issued a warrant authorizing law enforcement agents to seize the Bitcoin.
The assets had a market value of over $3.6 billion when the government took control of the private keys, special agent Christopher Janczewski noted in the press statement.
Bitfinex responded to the news of the seizure with a statement confirming its cooperation with the DOJ.
The exchange said it plans to work with the Justice Department in a bid to get the recovered funds, noting that it has a legal right "to a return of the stolen bitcoin."
The firm will give further updates on the matter, and promises to work towards an 18-month timeline of repurchasing and burning UNUS SED LEO tokens.
It expects to use 80% of the recovered funds to accomplish this, should the government hand over the BTC.