The suspects allegedly defrauded victims by luring them into entering fraudulent equipment rental contracts with a cryptocurrency mining service and investing in a fake virtual currency bank.
Two Estonian citizens were arrested in Tallinn after having been charged with their alleged involvement in a $575 million (€560m) cryptocurrency fraud and money laundering conspiracy, the US Justice Department revealed on Monday.
The accused duo, Sergei Potapenko and Ivan Turygin, both 37, are thought to have defrauded hundreds of thousands of victims through a multi-faceted scheme.
The department said that the two lured their victims into fraudulent equipment rental contracts with the defendants' cryptocurrency mining service called HashFlare.
Potapenko and Turygin also made victims invest in a fake virtual currency bank called Polybius Bank, which never paid out the promised dividends, the Justice Department said.
The US authorities further claimed that the victims paid over $575m to the alleged fraudster's companies and that they both subsequently used shell companies to launder the fraud proceeds and to purchase real estate and luxury cars.
The indictment was returned by a grand jury in the Western District of the northwestern US state of Washington on 27 October and unsealed on Monday.
A representative of both Potapenko and Turygin could not immediately be reached for comment.
"The size and scope of the alleged scheme is truly astounding," said Assistant Attorney General Kenneth Polite Jr of the Justice Department's criminal division.
"US and Estonian authorities are working to seize and restrain these assets and take the profit out of these crimes."
The department said that the case, which they claim was probed by the FBI, involved at least 75 real properties, six luxury vehicles and cryptocurrency wallets.