Throughout the trial, the Ulbricht's lawyer, Joshua Dratel, maintained that Ulbricht handed off the site to other operators shortly after he started it in 2011, and that he rejoined immediately prior to his arrest, lured back in by the new operators to serve as a fall guy.
For his closing remarks, Dratel did not offer an alternative explanation for key issues, such as how all the evidence of Silk Road's operations landed on Ulbricht's computer. He didn't need to, he explained to the jury: It was up to prosecutors to show Ulbricht was guilty "beyond a reasonable doubt." Instead he suggested a number of ways that such evidence could be forged, which he argued left enough doubt not to convict Ulbricht.
Prosecutors also brought a friend of Ulbricht's to the stand, Richard Bates, who described how he helped Ulbricht get Silk Road running in the early days of 2011.
To prove Ulbricht was active with Silk Road through 2012 and 2013 though, prosecutors relied almost entirely on digital evidence. Over the course of three weeks, prosecutors showed multiple instances of where digital evidence found on Silk Road servers overlapped with information found on Ulbricht's laptop and personal online accounts, such as his Gmail account and Facebook account. The laptop also contained thousands of pages of chat logs, in which Dread Pirate Roberts communicated worth other site administrators. The laptop also contained a personal journal that detailed many operations of the site.
Perhaps most damning for Ulbricht were the $18 million worth of bitcoins found on his laptop at the time of his arrest. In its opening statements, the defense had argued that these bitcoins were investment income unrelated to Silk Road. Yet, using the public bitcoin blockchain, which records all transactions, the prosecution was able trace at least $13 million worth of bitcoins being transferred from Silk Road servers directly to the bitcoin wallet on Ulbricht's laptop.
Early on in the trial, Dratel charged that Mark Karpeles, known for being the operator of the failed Mt. Gox bitcoin exchange, may have had a major hand in Silk Road's operations. Karpeles denied any involvement in Silk Road, and Judge Forrest ordered the jury to disregard the claim.