Ulbricht posted a comment on a Bitcoin forum in 2011 using his the email address email@example.com. The public Google+ profile associated with the account (which Google all but forces all users of Gmail to have), listed Ulbricht’s favorite YouTube videos, several of which were posted by the Mises Institute, which promotes the work of Austrian economist Ludwig von Mises. According to the complaint, the Mises Institute’s site allows users to create profiles. Ulbricht did.
So far, so innocent. But what clinched it for investigators is the Dread Pirate Roberts’s signature includes a link to the Mises Institute. He has also credited Austrian economic theory and Mises’s work as “providing the philosophical underpinnings for Silk Road,” according to the complaint.