http://www.forbes.com/sites/kashmirhill/2014/06/12/silk-road-bitcoin-on-the-move-as-government-prepares-to-auction-off-18-million-worth/The Bitcoin is a public ledger, and if your identity gets linked to a wallet or address, everyone can see when you move coins. That’s what happened to the feds Thursday. The federally-seized Bitcoin was moved out of the two addresses — here and here — where it had been stored, a huge transfer of funds that was noted by those watching Bitcoin activity such as market data app Zeroblock. The Bitcoin addresses had been notated on Blockchain.info as “Silk Road Seized Coin” and “DPR Seized Coins” (for Dread Pirate Roberts, the pseudonym assumed by Silk Road’s overlord).
The Federal Marshals are auctioning off seized digital money for the real stuff