Ross William Ulbricht, who was known by his digital handle,...

Ross William Ulbricht, who was known by his digital handle, Dread Pirate Roberts, was indicted in Manhattan Tuesday, Feb. 4, 2014, on charges he was the mastermind behind a secret website that brokered more than $1 billion in transactions for illegal drugs and services. This is an undated photo of Ulbricht. Credit: AP

The government blamed the founder of the Silk Road black market drug website for at least six overdose deaths and urged a federal judge to give him "substantially above" the mandatory minimum of 20 years in prison in a sentencing memo filed Tuesday.

Prosecutors depicted Ross Ulbricht, 30, a Texas-born Californian, as a remorseless drug "kingpin" and included a graphic portrait of one Silk Road victim -- a Microsoft employee found unresponsive in a chair at home with a hypodermic needle and an open express mail package linked to a Silk Road heroin order on his computer screen.

Ulbricht's sentencing is scheduled for Friday before Manhattan U.S. District Judge Katherine Forrest, who presided over his trial earlier this year.

In another Silk Road case, U.S. District Judge Thomas Griesa on Tuesday sentenced an Australian man who helped administer the website to just time served, about 17 months in prison.

Peter Philip Nash, 42, of Brisbane, a moderator on Silk Road discussion forums, pleaded guilty in March to narcotics trafficking and money laundering conspiracies. He faced up to life in prison, and at least 121 months under federal sentencing guidelines.

Nash, a counselor for the intellectually disabled in Australia, prosecutors said his role in Silk Road had been an "aberration" driven by his own drug addiction, and he had been a low level participant in Silk Road, hired online and paid about $25,000 for 9 months' work.

"It was never my intent to cause upset or harm, but needless to say that is what happened," Nash told the judge.

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