The FBI's evidence wasn't strong enough to even try him for this. Charges were dropped. If it happened the way the FBI said initially it would have been open and shut. But I guess they lied about what they had.
The charges were dropped only after Ulbricht was found guilty & sentence to life w/o parole on other charges. Why should I want the government to waste enormous amounts of $$$ for someone who is already going to spend the rest of their life in jail?