News of the arrest came only a week after 20,000 BTC from the Bitfinex hack was observed being moved. Although the DOJ didn't explicitly say that this movement led to the arrest, it seems like a safe bet.
The U.S. Department of Justice announced that they had arrested a New York couple and seized more than $3.6 billion in Bitcoin that they were allegedly trying to launder. The fortune was a portion of what was stolen in the 2016 Bitfinex breach, which saw the exchange lose around 120,000 BTC—then valued at around $71 million but worth around $4.5 billion at today's BTC prices. The husband and wife pair, Ilya Lichtenstein and Heather Morgan, both describe themselves as tech entrepreneurs; Morgan also describes herself as a "surrealist rapper", and her work sure is surreal.