Since his arrest in October 2013, alleged Silk Road mastermind Ross Ulbricht has maintained that the Bitcoins confiscated by the FBI do belong to him and are a result of early investments he made in the cryptocurrency – not proceeds from running an illegal online drug marketplace.

Prosecutors in the trial against Ulbricht presented evidence on Thursday that debunks that claim.

Former FBI special agent Ilhwan Yum took the stand to describe how he traced 3,760 Bitcoin transactions over the course of a year ending in August 2013. Based on data pulled from seized servers, all of those transactions lead back to Ulbricht’s Samsung 700z laptop – the same computer he was using (and logged into Silk Road) when he was arrested.

Based on exchange rates at the time of each transaction, the coins were worth roughly $13.4 million.

The evidence against Ulbricht continues to mount in the case. Thus far, prosecutors have detailed a journal they found that details the site’s creation and heard testimony from a college friend that claims Ulbricht confessed that he created the site.

The latter statement isn’t up for dispute, however, as Ulbricht’s attorney Joshua Dratel said his client did create the site but only as an economic experiment. After a few months of operating the site, Ulbricht claims he handed it off to others and was lured back as a patsy just before police closed in to take the fall.

Dratel has also suggested that Dread Pirate Roberts, the online moniker of the person or persons that ran Silk Road, may have been Mark Karpeles, the CEO of embattled Bitcoin exchange Mt. Gox.