She called herself the "Cryptoqueen" and touted her purported new digital currency, OneCoin, as the next big thing.

But after convincing investors around the world to send her $4 billion, federal prosecutors say, Ruja Ignatova quietly hopped a flight to Greece and disappeared.

OneCoin, authorities say, was a scam. On Thursday, the FBI placed the alleged fraudster on the 10 Most Wanted list, days after Europol did the same.

At a news conference Thursday, Damian Williams, U.S. attorney for the Southern District of New York, called her "an international fugitive who allegedly masterminded a worldwide fraud."

"Now she sits side by side on the Top 10 list with cartel leaders, murderers and terrorists," Williams said. "That’s no accident."

Authorities say OneCoin was one of the largest pyramid schemes in modern history. Although Ignatova claimed it was backed by a blockchain, prosecutors said there was none — she made up the price. The coins were not traded.

When the Justice Department unsealed its indictment against Ignatova in 2019, then-FBI Assistant Director-in-Charge William Sweeney Jr. said: “OneCoin was a cryptocurrency existing only in the minds of its creators and their co-conspirators. Unlike authentic cryptocurrencies, which maintain records of their investors’ transaction history, OneCoin had no real value. It offered investors no method of tracing their money, and it could not be used to purchase anything. In fact, the only ones who stood to benefit from its existence were its founders and co-conspirators.”

Ignatova, now 42, was a resident of Sofia, Bulgaria, before she fled. She is charged with one count each of wire fraud, conspiracy to commit wire fraud, securities fraud and conspiracy to commit money laundering, with each count carrying a maximum sentence of 20 years in prison.