Remember the trove of bitcoins nabbed from the illicit underground market Silk Road? The US Marshals have been slowly auctioning them off in batches, something we've been reporting on over past months. The end of this week saw yet another bitcoin batch auction, but it was more notable for one big reason: it was the last of them. The auction took place on March 5 starting at 8AM, with registered bidders being able to email in bids for a batch of 50,000 bitcoins (split up into smaller blocks). Who bought the digital currency has not been revealed.