The operators of two exchanges for the virtual currency Bitcoin have been arrested in the US. The Department of Justice said Robert Faiella, known as BTCKing, and Charlie Shrem from BitInstant.com have both been charged with money laundering. The authorities said the pair were engaged in a scheme to sell more than $1m (£603,000) in bitcoins to users of online drug marketplace the Silk Road. The site was shut down last year and its alleged owner was arrested. Mr Shrem was arrested on Sunday at New York's JFK airport. He was expected to appear in court on Monday, prosecutors said....