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Ross William Ulbricht – alleged founder of Silk Road.
Ross William Ulbricht has been indicted on charges he was the mastermind behind Silk Road, a website alleged by US prosecutors to have brokered more than $US1bn in transactions for illegal drugs and services.

An indictment unsealed in New York on Tuesday charges Ulbricht, 29, with drug trafficking, computer hacking, money laundering and other counts.

A lawyer for Ulbricht, Joshua Dratel, said his client would plead not guilty on Friday. "The indictment was expected and does not contain any new factual allegations," Dratel said in a statement.

Ulbricht was arrested late last year. Authorities say he operated the Silk Road website under the name Dread Pirate Roberts. The website allowed users to anonymously browse nearly 13,000 listings.

Authorities say the categories included cannabis, psychedelics and stimulants. Purchases were made using the virtual currency Bitcoin.

Ulbricht was arrested on 1 October in a public library in San Francisco, shortly after authorities shut down Silk Road, which vendors and customers accessed using an encryption program that strips internet users' identifying information to allow them to communicate anonymously with each other.

Ulbricht has maintained his innocence through statements by his lawyer.

The indictment by a grand jury marks the end of an initial period during which Ulbricht could have talked with prosecutors and made a deal to soften any sentence rendered against him by pleading guilty and co-operating.