There's a lot of confusion around this. They are selling the Bitcoins that were on the Silk Road servers. There were other Bitcoins on his computers. He said he owned the ones on his computer, but not the ones on the Silk Road servers (because he denies being involved with Silk Road.) At that point, the DOJ posts a notice saying "hey, anyone who thinks they own these, come forward and make a claim." No one did, so they are now at the "sell them off" stage.