In what is being described as the "largest financial seizure ever," a married couple known as "Bitcoin Bonnie and Crypto Clyde" have pleaded guilty to laundering $4.5 billion in stolen cryptocurrency. Heather Morgan, an online rapper who goes by the name "Razzklekhan," and her husband, Ilya Lichtenstein, a New York technology entrepreneur, were arrested last year after their extravagant lifestyle raised suspicions of involvement in a crypto heist.

The couple's arrest came after an investigation by the US Justice Department, which managed to recover $2.8 billion out of the total stash of stolen bitcoin, which is now valued at $3.5 billion. Prosecutors have revealed that the pair stole the bitcoin in 2016 using sophisticated hacking tools.

As part of their plea deal, Lichtenstein admitted to being the mastermind behind the hack, while Morgan pleaded guilty to money laundering and an additional count of conspiracy to defraud the US. Despite attempting to hide their crimes, Morgan had been posing as a successful tech businesswoman and even claimed to be a rapper and tech entrepreneur in articles published in Forbes.

Lichtenstein entered his guilty plea at a hearing before US District Judge Colleen Kollar-Kotelly in Washington. His wife, Morgan, is expected to enter her own plea later on Thursday. She faces an additional charge of conspiracy to defraud the United States.

The stolen bitcoin, which was worth $71 million at the time of the hack, had appreciated to over $4.5 billion by the time the couple was apprehended. Deputy Attorney General Lisa Monaco stated that the $3.6 billion in assets recovered from the couple represents the largest financial seizure in the history of the US Department of Justice. Prosecutors are now seeking to have the couple forfeit $3 billion.

The case has sent shockwaves through the cryptocurrency community, highlighting the need for robust security measures. The hacking incident at Bitfinex, one of the world's largest cryptocurrency exchanges, exposed vulnerabilities within the industry and has raised concerns about the safety of digital assets.

The plea deal reached between Lichtenstein, Morgan, and the US Attorney's office in Washington marks a significant milestone in the investigation. The couple's guilty pleas and the recovery of a substantial portion of the stolen funds serve as a warning to those involved in cryptocurrency-related crimes. The case also serves as a reminder that even the most advanced hackers can be brought to justice.