Image copyright AP Image caption Ross William Ulbricht filed a claim contesting the seizure of $150m of Bitcoins

The US has charged a California man alleged to be the owner of Silk Road, a black-market website that brokered $1bn (£613m) in transactions.

Ross William Ulbricht, 29, is accused of drug trafficking, computer hacking and money laundering.

Prosecutors allege he deliberately operated the site as a criminal enterprise and solicited six murders-for-hire.

Mr Ulbricht's lawyer says his client will plead not guilty to all charges.

"The indictment was expected and does not contain any new factual allegations," Joshua Dratel said in a statement. "We look forward to preparing Ross' defence."

Authorities say Mr Ulbricht operated the Silk Road site under the name Dread Pirate Roberts, an apparent reference to the movie The Princess Bride. Purchases were made using the virtual currency Bitcoin.

He was arrested last year as the site was shut down by the FBI. Officials seized 173,991 Bitcoins ($150m) as part of the investigation.

Mr Ulbricht has filed a claim contesting the seizure of the Bitcoins, asserting that they were found on his personal computer and belong to him rather than Silk Road.

He is also accused of conspiring to have a former Silk Road employee murdered during the course of a federal sting operation.

That murder-for-hire, along with the others, was never carried out.

Silk Road allowed visitors to browse nearly 13,000 listings, many of them for illegal drugs, but also offered forged documents, computer hacking services and pirated media content, prosecutors said.