It was a gripping tale of peril and prowess that captivated the world for more than two tense weeks in the summer of 2018. Twelve boys and their football coach were lost in a subterranean maze in the Tham Luong caves in Thailand. An international team of cave divers raced to rescue them before monsoon rains were due to flood the caves. The story was destined to be fodder for a Hollywood blockbuster – and that was before an eccentric billionaire got involved.

On Tuesday, a postscript to the feelgood tale of the Tham Luang cave rescue played out in a federal courthouse in Los Angeles as the trial began in a defamation case brought by the British caver Vernon Unsworth against Tesla’s chief executive, Elon Musk.

Musk testified on Tuesday that he was being insulting, not literal, when he called Unsworth a pedophile in a tweet after the diver had ridiculed Musk on CNN. Musk said he was upset the diver had belittled his efforts to help by building a miniature submarine to transport the boys.

Unsworth’s comments were “an unprovoked attack on what was a good-natured attempt to help the kids”, Musk said. “It was wrong and insulting, and so I insulted him back.”

Unsworth, a British national who lives in Thailand, was among the first divers to reach the scene of the boys’ disappearance. He was credited by rescuers for his detailed knowledge of the cave system, which helped locate the missing team.

Musk, the chief of Tesla and SpaceX, had assigned a team of engineers to design a submarine that he hoped could be used to guide the boys through underwater tunnels. Although Musk delivered the submarine to the rescue site, the boys were rescued by divers, one of whom died during the operation.

Unsworth drew the ire of Musk following the rescue when he gave a brief interview to CNN and ridiculed his submarine, which he said “had absolutely no chance of working”. He added that Musk should “stick his submarine where it hurts”.

The billionaire entrepreneur lashed out at Unsworth on Twitter, where he called the caver a “pedo guy” to his 22 million followers. Under intense criticism from the public and his company’s investors, Musk apologised and deleted the tweets, but he subsequently revived the baseless allegations in another series of tweets about a month later. Musk also alleged in another baseless allegation that Unsworth was a “child rapist” in an email to a BuzzFeed reporter.

The jury selection process demonstrated Musk’s fame. Numerous members of the jury pool disclosed business ties to Musk’s various companies, which include Tesla, SpaceX, the Boring Company, Open AI and Neuralink. Four potential jurors were Tesla owners. One was dismissed when he said he could not be objective about the case because he was about to interview for a job with SpaceX, while two others were let go after saying they followed Musk on Twitter and knew the details of the case.

Only one potential juror, an aesthetician, admitted to having strong opinions about billionaires. She was dismissed. Another juror had “negative and positive” opinions about Musk, and he was allowed to remain.

Attorneys for Unsworth and Musk sketched the contours of their cases in opening statements before the eight empaneled jurors. Taylor Wilson, part of Unsworth’s legal team, focused on the number of times that Musk could have, but did not, clarify or retract his remarks about Unsworth.

“It wasn’t until a year later that Musk said in a deposition that ‘pedo guy’ just meant ‘creepy old guy’,” Wilson said. The result of Musk’s statements was “shame, mortification, worry and distress”, he added, “during what should have been one of the proudest moments in [Unsworth’s] life”.

Musk’s attorney, Alex Spiro, dismissed Unsworth’s defamation claim, casting the case as “insults between two men”. “He’s saying he’s been horribly damaged and he deserves lots of money,” Spiro said of Unsworth. “He doesn’t.”

Spiro described the “sleepless nights” Musk’s engineers spent “frantically trying to help” the boys. He cast Unsworth as the aggressor in the pair’s interactions, noting that the rescue was over and Musk had returned to the US when Unsworth gave his interview to CNN.

“When he saw this attack it did anger and hurt him,” Spiro said of Musk. “The real hurtful part was attacking the genuineness of his efforts. That could not go unanswered.”

Calling Unsworth a “pedo guy” was not an allegation of pedophilia, but instead a “fill-in-the-blank insult”, the attorney argued. Spiro also introduced an acronym that appears likely to feature heavily in his arguments to come: J-Dart. “It was a joking, deleted, apologized for, responsive tweet,” he said. “A J-Dart.”

Spiro also said Unsworth had not been harmed by Musk’s statements, noting that the cave explorer had since been honored by Queen Elizabeth and Thailand’s King Maha Vajiralongkorn, among others.

Later on Tuesday, Musk himself took the witness stand.

Musk testified that his Twitter message was sent in response to an “unprovoked” insult he received from Unsworth.

“I thought he was just some random creepy guy,” Musk added. “I thought at the time that he was unrelated to the rescue.”

Highlights so far:

- Musk used to have google alerts for his name but no longer does.

- He watched video of Unsworth criticizing him 2-3 times before tweeting “pedo guy”

- If Musk had really thought Unsworth was a pedo, he would have bet more than $1



https://t.co/dVmhYBNoSV — Julia Carrie Wong (@juliacarriew) December 3, 2019

Musk said he didn’t know Unsworth had helped with the rescue and that his tweet wasn’t intended as an actual allegation. “Just as I hadn’t literally meant he was a pedophile, he didn’t want to shove a sub up my ass,” Musk said.

Tuesday’s trial follows a year of legal wrangling between Unsworth and Musk’s attorneys. Musk had attempted to have the case dismissed, arguing at one point that “pedo guy” is a common insult in his home country of South Africa and was not intended as an actual accusation of pedophilia. Court filings revealed that Musk had also hired a private investigator to attempt to substantiate his allegations against Unsworth.

The US district judge Stephen Wilson ruled in November that Unsworth was not a public figure, lowering the bar for the cave explorer to prove that Musk had defamed him.

The Associated Press contributed to this report