Elon Musk (Courtesy photo)

Updated with a quote from Musk's counsel at 12:05 PT on 10/29/19

A federal judge in San Francisco will not allow lawyers for Elon Musk to depose a journalist from Buzzfeed who reported on emails the tech CEO designated "off the record" in an article that's ended up at the center of a defamation lawsuit.

U.S. Magistrate Judge Jacqueline Scott Corley on Monday found that the proposed deposition wouldn't be relevant to Musk's defense and that it wasn't reasonably foreseeable Buzzfeed would publish emails he marked as "off-the-record" and "on background" to reporter Ryan Mac, with whom the tech CEO had had no interaction prior to sending the emails.

"Reasonable foreseeability is predicated on the state of mind of the originator of the defamatory matter (Mr. Musk) and not the secondary publisher (Mr. Mac or BuzzFeed)," Corley wrote in Monday's 12-page order.

Corley, however, will allow lawyers for British cave explorer Vernon Unsworth, the man suing Musk for defamation, to depose Mac for the limited purpose of establishing that there were no communications between the Buzzfeed reporter and Musk besides the emails and that BuzzFeed published the emails at issue.

The dispute between Unsworth and Musk that led to the defamation suit broke out in the wake of the rescue of a Thai youth soccer team from a flooded cave last year in which both participated. Unsworth, in a July 2018 interview with CNN, called a submersible tube Musk designed for the rescue effort a "PR stunt" and said Musk "can stick his submarine where it hurts."

Musk responded in a now-deleted Twitter message that he and his team never saw "this British expat guy who lives in Thailand (sus)" while working at the caves. "Sorry pedo guy, you really did ask for it," Musk added. Musk deleted the "pedo guy" tweet and apologized on Twitter on July 18. But according to Unsworth's lawsuit, filed in the Central District of California by high-profile defamation lawyer L. Lin Wood, Musk continued to press his allegations that Unsworth was a pedophile in his email exchange with Mac, resulting in further coverage.

"As a percipient witness to some of the communications at issue in the underlying action, Mr. Mac's testimony is relevant to Mr. Unsworth's claim," Corley wrote in Monday's order. "While these facts appear to be undisputed by Mr. Musk, Mr. Mac is beyond the subpoena power of the Central District of California and thus Mr. Unsworth cannot compel him to testify at trial; Mr. Unsworth is entitled to preserve Mr. Mac's testimony in the event Mr. Musk takes a different position at trial."

Corley issued a protective order limiting the deposition to the topics Unsworth's lawyers have laid out, finding that Musk's lawyers had asked to depose Mac or some other corporate representative of Buzzfeed about "irrelevant and harassing topics" including the news organization's coverage of Musk, Tesla and SpaceX, its method for determining pay based on article popularity, and its guidelines for reporter's use of social media. Corley concluded the protective order was especially needed in this case where "the record suggests Mr. Musk feels animus toward non-party Mr. Mac."

In an email statement passed along by spokesman, Musk's lead lawyer, Alex Spiro of Quinn Emanuel Urquhart & Sullivan said: "Mr. Mac has been ordered to sit for a deposition — end of story."

Wood, Unsworth's lawyer, said in an email that "Judge Corley got it exactly right."

Davis Wright Tremaine's Katherine Bolger, who represents Mac and Buzzfeed, didn't immediately respond to a message Tuesday morning. Mac, who changed his Twitter handle to "Non-Party Mr. Mac," noted the order in a post Monday night: