*Updated with Judge Katherine Forrest's ruling on the prosecution's motion below.

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The trial of Ross Ulbricht hinges on proving that Ulbricht is the Dread Pirate Roberts, a shadowy, pseudonymous kingpin who ran the massive online narcotics market known as the Silk Road. But as the case enters its second week, the prosecution wants to prevent Ulbricht's defense lawyers from mentioning before a jury one potential clue—or red herring—in that mystery: the transcript of a conversation the Dread Pirate Roberts had with me.

In a motion filed Monday afternoon, prosecutors have asked Judge Katherine Forrest to stop the defense from questioning a witness, Department of Homeland Security special agent Jared Der-Yeghiayan, about his belief in 2012 and 2013 that another suspect—Mark Karpeles, the CEO of bitcoin exchange Mt. Gox—was actually the Silk Road's Dread Pirate Roberts. And as part of their argument, prosecutors have specifically asked the judge to prevent the defense from bringing up a written interview I conducted with the Dread Pirate Roberts in 2013 for Forbes Magazine, the only extensive interview the Silk Road's masked drug lord ever gave.

That interview could be relevant to the case for two reasons. First, the DHS's special agent Der-Yeghiayan read the interview in 2013 and emailed it to his colleagues, noting that the Dread Pirate Roberts' writing "sounds very much like" his suspect, Mark Karpeles. And second, the Dread Pirate Roberts told me in that interview that he hadn't actually created the Silk Road, but instead had befriended its creator and later acquired the site from him. That second point in particular now seems to match up with the story defense attorney Joshua Dratel told about his client in opening arguments: that Ulbricht did in fact create the Silk Road, but after just a few months handed over its ownership and management to the "real" Dread Pirate Roberts, who remains at large today.

The prosecution, however, argues that the DHS witness testifying about the article would constitute "hearsay"—the legal term for a witness's secondhand account based on something someone else wrote or said, which is inadmissible as evidence. "The article itself is clearly hearsay and cannot be introduced through [special agent] Der-Yeghiayan’s testimony," the prosecutors write in their letter to the judge. "Indeed, it is double-hearsay. The statement was initially made by the 'Dread Pirate Roberts,' and was then reported by a journalist. There is of course no reason to assume the reliability of the reported statement."

>An FBI staffer told me that the person I had interviewed in July was indeed Ulbricht, and that he had lied to me about the Silk Road's multiple owners to throw off investigators.

Hearsay or not, the story of how the Dread Pirate Roberts acquired the Silk Road was one of the first things Roberts told me in our five-hour, wide-ranging interview on July 4, 2013 over the Silk Road’s anonymized messaging system. (Over the course of eight months, I had chatted with the Dread Pirate Roberts on Silk Road forums to set up that on-the-record Q&A; I'm confident that only Roberts would have access to that username in the Silk Road system.) And as the Silk Road's kingpin described it, he found a security vulnerability in the site early in its time online that would have allowed an attacker to steal the bitcoins users spent to make purchases in its anonymous online market. Roberts told me that he reported the flaw to the Silk Road's owner, thereby gaining his trust, and then later took over full control of the site. "I was in his corner from early on and eventually it made sense for me to take the reigns," Roberts wrote to me. "He was well compensated and happy with our arrangement. It was his idea to pass the torch in fact."

That statement, of course, couldn't be confirmed. Less than three months after the interview, Ross Ulbricht was arrested in a San Francisco public library. In a phone call following that arrest, an FBI staffer told me that the person I had interviewed in July was indeed Ulbricht, and that he had lied to me about the Silk Road's multiple owners to throw off investigators. In its motion Monday, the prosecution made a similar argument, calling the story "a self-serving statement of the defendant himself."

In theory, none of the jurors in the case will know of the interview's existence unless the judge allows the defense to mention it. All the jurors were selected for having no prior knowledge about the Silk Road, and then carefully instructed by judge Forrest not to read any outside media coverage about it. Forrest even warned the jurors on Thursday not to watch the Princess Bride, the fantasy film in which the "Dread Pirate Roberts" pseudonym originated.

In court last Thursday, defense attorney Joshua Dratel told the judge (without the jury present) that he planned to bring up the Dread Pirate Roberts interview in his cross examination of DHS agent Der-Yeghiayan, but only to have Der-Yeghiayan say that he had had read it and wrote in a 2013 email to colleagues that its words sounded like the suspect Mark Karpeles rather than Ulbricht. Dratel assured the judge he didn't plan to focus on the Dread Pirate Roberts' statement about multiple Silk Road owners.

But in its followup letter to the judge, prosecutors still seem concerned that Dratel could use Der-Yeghiayan's email about the interview to introduce its mention of the Silk Road's handoff. "In [the article] the reporter relayed that the 'Dread Pirate Roberts' stated that he had bought out the previous owner of Silk Road," the prosecutors write. "The defense, it is clear, is seeking to offer this statement for its truth."

In a response to the prosecution's motion Monday night, Ulbricht's defense again assured Judge Forrest that it won't bring up the "substance" of the interview before the jury, though it still argues that Der-Yeghiayan's email about the interview should be admissible as evidence.

Whether the judge decides to let the defense bring up any mention of the interview will likely be decided today, when Dratel's cross-examination of DHS agent Der-Yeghiayan resumes. If the jurors do at any point hear the account the Dread Pirate Roberts' told me, their opinion of "its truth"—as the prosecution puts it—could be a far more complicated question.

Update: In a ruling Tuesday morning, Judge Forrest sided with the prosecution, saying that agent Der-Yeghiayan's "belief" that my interview with Dread Pirate Roberts might be Mark Karpeles was indeed hearsay, and not "competent evidence." That decision will prevent the defense from bringing it up, at least in its cross examination of Der-Yeghiayan. "Whether [Der-Yeghiayan] believed the interview was with the man on the moon or Karpeles doesn't matter," Forrest said.