US prosecutors told a judge that the mastermind behind one of the largest cryptocurrency heists ever should be sentenced to five years in prison for a money laundering conspiracy related to the $6 billion hack of Bitfinex exchange.

The US government said in a court filing on Tuesday that Ilya Lichtenstein, who pleaded guilty last year, should spend more time in prison than his rapper wife and co-conspirator Heather Morgan. Last week, prosecutors said Morgan, who calls herself the "Wall Street crocodile," should be sentenced to 18 months in prison.

Prosecutors said Lichtenstein fits the profile of a young cybercriminal whose online activities "normalize in a way that downplays the impact on victims."