The US crackdown on Bitcoin has been long in coming, with ebbs and flows of enforcement as regulators have been unsure exactly how to proceed with dismantling the digital fiat alternative. This morning the ebb became a rising tide, after U.S. prosecutors announced charges against two men operating Bitcoin exchange businesses for attempting to sell $1 million worth of Bitcoin to users of the underground black market website Silk Road, which was shut down by authorities in September.

Reuters reports that the U.S. Attorney's office in Manhattan said in a statement that authorities arrested Charlie Schrem, chief executive officer of the exchange BitInstant.com, on Sunday and Robert Faiella, who ran an underground Bitcoin exchange called BTCKing, on Monday. The two were charged with conspiring to commit money laundering and operating an unlicensed money transmitting business. Schrem is also vice president of the main Bitcoin-focused trade group, the Bitcoin Foundation, according to the foundation's website and Schrem's LinkedIn profile.