WASHINGTON—The Justice Department said Tuesday it seized over $3.6 billion worth of digital currency stolen during a hack of a cryptocurrency exchange and arrested two suspects for allegedly trying to launder the proceeds.

The value of the cryptocurrency at the time it was seized last week marks the largest financial seizure ever by the Justice Department, officials said.

Ilya...

WASHINGTON—The Justice Department said Tuesday it seized over $3.6 billion worth of digital currency stolen during a hack of a cryptocurrency exchange and arrested two suspects for allegedly trying to launder the proceeds.

The value of the cryptocurrency at the time it was seized last week marks the largest financial seizure ever by the Justice Department, officials said.

Ilya Lichtenstein, 34 years old, and his wife, Heather Morgan, 31, were both arrested without incident Tuesday morning in Manhattan, the department said. They are scheduled to make their initial court appearances Tuesday afternoon.

According to court documents, the suspects allegedly conspired to launder nearly 120,000 bitcoin stolen from Bitfinex’s platform in 2016 after a hacker breached the exchange’s systems and initiated more than 2,000 unauthorized transactions. The transactions funneled the stolen bitcoin to a digital wallet being controlled by Mr. Lichtenstein, federal prosecutors said.

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Write to Dustin Volz at dustin.volz@wsj.com