Two Bitcoin executives have been charged in the U.S. with conspiring to commit money laundering by selling more than $1 million of the digital currency to users of an illicit online drugs bazaar ‘Silk Road’.

U.S. Attorney Preet Bharara brought the criminal charges in Manhattan federal court against underground Bitcoin exchanger Robert Faiella, 52, and Chief Executive Officer and Compliance Officer of a Bitcoin exchange company Charlie Shrem, 24.

The two have been charged with conspiring to commit money laundering, and operating an unlicensed money transmitting business.

“As alleged, Robert Faiella and Charlie Shrem schemed to sell over $1 million in Bitcoins to criminals bent on trafficking narcotics on the dark web drug site, Silk Road,” Mr. Bharara said.

“Truly innovative business models don’t need to resort to old-fashioned law-breaking, and when Bitcoins, like any traditional currency, are laundered and used to fuel criminal activity, law enforcement has no choice but to act. We will aggressively pursue those who would co-opt new forms of currency for illicit purposes,” he said.

Shrem, also the Vice Chairman of a foundation dedicated to promoting the Bitcoin virtual currency system, is charged with failing to file any suspicious activity report regarding Faiella’s illegal transactions through the company in violation of federal laws.

Shrem, considered one of the most prominent players in the Bitcoin space, was arrested on Sunday at the city’s John F. Kennedy International Airport. Faiella was arrested at his residence in Florida and would be presented in federal court there. The two face upto 25 years in prison.

According to allegations in the criminal complaint, Faiella ran an underground Bitcoin exchange on the Silk Road website, which served as a sprawling and anonymous black market where illegal drugs of virtually every variety were bought and sold regularly by the site’s users.

Operating under the username ‘BTCKing’, Faiella sold Bitcoins — the only form of payment accepted on Silk Road — to users seeking to buy illegal drugs on the site.

Faiella received orders for Bitcoins from Silk Road users and filled the orders through a New York-based company.

The company was designed to enable customers to exchange cash for Bitcoins anonymously, without providing any personal identifying information, and it charged a fee for its service.

Shrem was a co-founder and chief executive of a popular website BitInstant. The company won the backing of Winklevoss Capital Management, which is run by the Winklevoss twins, who were early players in Facebook.

After the arrests, the Winklevoss brothers said in a statement that they “are obviously deeply concerned about his arrest”, and “support any and all governmental efforts to ensure that money-laundering requirements are enforced”.