A week ago, 24-year-old Charlie Shrem landed at JFK, home from giving a talk about the virtual currency Bitcoin at an e-commerce convention in Amsterdam. But as soon as he saw the agents from the Drug Enforcement Administration and IRS waiting for him at the gate, he knew. Shrem had never been arrested before, but a magistrate detailed a list of felony charges against him the next morning: one count of conspiracy to commit money laundering, one count of failure to file a suspicious activity report, and one count of operating an unlicensed money transmitter, together carrying a maximum sentence of 25 years in prison. He started investing in Bitcoin as a senior at Brooklyn College, buying many thousands when the coins were around $3 or $4 each (they’re now over $800), but his notoriety didn’t come until BitInstant, the Bitcoin payments company he cofounded that was profitable almost from day one.