WASHINGTON — A hacker has been sentenced to five years in a US prison for laundering the proceeds of one of the biggest ever cryptocurrency thefts.

Ilya Lichtenstein pleaded guilty last year in the case involving the Bitfinex cryptocurrency exchange being hacked in 2016 and the theft of almost 120,000 bitcoins.

He laundered the stolen cryptocurrency with the help of his wife Heather Morgan, who used the alias Razzlekhan to promote her hip hop music.

At the time of the theft, the bitcoin was worth around $70m (£55.3m), but had risen in value to more than $4.5bn by the time they were arrested. At today's prices they would be worth more than double that.

The $3.6bn worth of assets recovered in the case was the biggest financial seizure in the Department of Justice's history, Deputy Attorney General Lisa Monaco said at the time.

“It’s important to send a message that you can’t commit these crimes with impunity, that there are consequences to them,” district judge Colleen Kollar-Kotelly said.

Lichtenstein, who has been in prison since his arrest in February 2022, expressed remorse for his actions.

He also said that he hopes to apply his skills to fight cybercrime after serving his sentence.

Morgan also pleaded guilty last year to one count of conspiracy to commit money laundering. She is due to be sentenced on 18 November.

According to court documents, Lichtenstein used advanced hacking tools and techniques to hack into Bitfinex.

Following the hack, he enlisted Morgan's help to launder the stolen funds.

They "employed numerous sophisticated laundering techniques", the Department of Justice said in a statement.

The methods included using fictitious identities, switching the funds into different cryptocurrencies and buying gold coins.

Lichtenstein, who was born in Russia but grew up in the US, would then meet couriers while on family trips and move the laundered money back home, prosecutors said.

Morgan's Razzlekhan persona went viral on social media when the case emerged.

Even as the couple attempted to cover up the hack, she published dozens of expletive-filled music videos and rap songs filmed in locations around New York.

In her lyrics she called herself a "bad-ass money maker" and "the crocodile of Wall Street".

In articles published in Forbes magazine, Morgan also claimed to be a successful technology businesswoman, calling herself an "economist, serial entrepreneur, software investor and rapper". — BBC