US to auction seized Silk Road Bitcoins worth $18m Published duration 13 June 2014

image copyright US MARSHALS SERVICE image caption The US Marshals Service announced the auction on its website

The US government will auction $18m (£11m) worth of the virtual currency Bitcoin, which was seized by the FBI when it shut down the Silk Road online marketplace in October last year.

The site, which operated on the so-called "dark net", traded in drugs and other illegal goods.

Payments were made via crypto-currencies, to ensure anonymity.

The Bitcoins were seized during the arrest of Ross Ulbricht, the alleged mastermind behind Silk Road.

The 29-year-old, who was known online by the pseudonym Dread Pirate Roberts, or DPR, is currently awaiting trial on narcotics trafficking, computer hacking and money laundering offences.

In a statement , the US Marshals Service, which is conducting the sale, said the 29,656.51306529 Bitcoins up for auction were those that had "resided on Silk Road servers", but did not include the stash on Ross Ulbricht's personal computers.

Ulbricht's "wallets" are thought to be worth more than $85m at current Bitcoin exchange rates. He is contesting the claim that the money was earned illegally.

The Bitcoins offered in this auction have been forfeited to the US government.

The US authority added that it would "not sell to any person who is acting on behalf of or in concert with the Silk Road and/or Ross William Ulbricht, and bidders will be required to so certify".

Last year, Carnegie Mellon University estimated that over $1.22m (£786,183) worth of trading took place on the Silk Road every month.

Prospective bidders will have to put forward a deposit of $200,000, and all offers must be made in cash.

The price of Bitcoin, as measured by CoinDesk, fell following news of the sale, but has since made a modest recovery.

The bidding process will begin on 27 June.