Prosecutors on Friday told a federal judge that the mastermind of the nefarious online bazaar Silk Road is too dangerous to be freed on bail.

Ross William Ulbricht, also known as "Dread Pirate Roberts," wore a green T-shirt under red jail clothes, his ankles shackled, as a public defender argued for time to figure out acceptable conditions for bail pending trial.

Federal magistrate Joseph Spero appeared doubtful, asking defense attorney Brandon LeBlanc whether seeing the criminal indictment that includes a murder-for-hire charge had "changed his calculus" regarding the chances of Ulbricht being freed pending trial.

Spero granted a request by LeBlanc to postpone the detention hearing to October 9.

Ulbricht stood straight and appeared alert, nodding and saying "OK" when Spero set a new date for a hearing at which his finances and potential for bail will be discussed.

Federal prosecutor Randall Luskey opposed the delay, telling Spero that the government wants Ulbricht to stand trial in Maryland where the indictment was issued and that no conditions would offset the danger he represented to the community and the likelihood he would flee.

Ulbricht, 29, was arrested this week by US authorities who accuse him of being the mastermind behind an online black market for drugs, hitmen, hacker tools and more, arresting the suspected mastermind of a nefarious bazaar called Silk Road.

Prosecutors also charged that in March, Ulbricht tried to hire someone to kill a Silk Road user who threatened to expose the identities of others using the website.

"We deny all charges and that is the end of the discussion at this point," LeBlanc said outside the courtroom.

Federal agents shut down the website, which used a privacy-protecting Tor network and Bitcoin digital currency to shield the identities of buyers and sellers around the world.