The brother of "cryptocurrency queen" Ruja Ignatova is back at large. He spent about three years behind bars for his involvement in the infamous OneCoin fraud scheme worth $4.4 billion.

OneCoin was a Ponzi scam based in Bulgaria that was run between 2014 and 2018. The fraudsters promised outsized profits, guaranteed returns and marketed their crypto project as a "Bitcoin killer."

According to a Bloomberg report, the remorseful Konstantin Ignatov has now been released by US District Judge Edgardo Ramos because he had already sufficiently served his prison sentence. The crypto fraudster was arrested back in 2019.

Ignatov had pleaded guilty to his involvement in the OneCoin cryptocurrency scam following the disappearance of his sister in 2017. At the time of the most recent verdict, he had already spent 34 months in prison.

However, the judge was full of praise for Ignatov's cooperation with the prosecution, which was merciful as a result. Nevertheless, he clearly described OneCoin as a "large-scale fraud with hundreds of thousands of victims" who could hardly hope for compensation.

Ignatov's cooperation also included his testimony in the trial of former attorney Mark Scott. Scott was sentenced to 10 years in prison for laundering US$400 million from the OneCoin scam.

Ignatov, however, is allowed to move freely only under certain conditions. He must be under preliminary court supervision for the next two years and also hand over US$118,000 from his activities at OneCoin.

The whereabouts of his sister, the "Cryptoqueen" Ignatova, are still unknown. She is currently on the FBI's "Ten Most Wanted" list and was convicted in absentia of securities fraud and money laundering, among other charges.