Elon Musk testifies in defamation trial over his tweet about British cave diver

Elon Musk testified at his defamation trial on Tuesday, arguing that his inflammatory Twitter message at the centre of the case was sent in response to an "unprovoked" insult he received from the man now suing him.

Musk, the billionaire chief executive of Tesla, was the first witness to testify in the lawsuit brought by a British cave diver who gained fame for his leading role in the rescue of 12 boys and their soccer coach from a flooded cave in Thailand last year.

The diver, Vernon Unsworth, says Musk, who also founded the rocket company SpaceX, falsely labelled him a pedophile on Twitter and should pay punitive and other damages for harming Unsworth's reputation.

The case stems from an offer Musk made to furnish a mini-submarine from SpaceX to assist in the cave rescue in July 2018.

Unsworth told CNN on July 13, 2018, three days after the rescue was completed, that Musk's offer was a "PR stunt" and that Musk should "stick his submarine where it hurts."

Two days later, Musk lashed out at Unsworth in a series of tweets, including one which called the cave diver a "pedo guy." Musk later apologized for the comment, saying it was a common insult in South Africa where he grew up.

Unsworth called the slur a lie that has harmed his reputation.

Musk was called to testify after a jury was selected to hear the case and the two sides delivered opening statements.

Musk said he was merely responding in kind to Unsworth's remarks. Those comments were "an unprovoked attack on what was a good-natured attempt to help the kids," Musk testified in federal court in Los Angeles. "It was wrong and insulting, and so I insulted him back."

"I thought [Unsworth] was just some random creepy guy," Musk added. "I thought at the time that he was unrelated to the rescue."

Pressed under questioning by lawyer Lin Wood, Musk testified that he did not mean for his tweet about Unsworth to be taken literally.

"I assume he did not mean to sodomize me with a submarine ... Just as I didn't literally mean he was a pedophile," he said.

"I apologized in a tweet and again in the [pretrial] deposition, and I'll say it again — I apologize to Mr. Unsworth," Musk said looking directly at the plaintiff, who sat stone-faced through Musk's testimony.

Musk was expected to return to the witness stand on Wednesday for more questioning by his own lawyers.

Unspecified damages

The judge explained the case hinges on whether a reasonable person would take Musk's Twitter statement to mean that he was calling Unsworth a pedophile.

Despite removing the tweets, Musk later suggested in emails to the news website BuzzFeed that Unsworth was a "child rapist" and had moved to northern Thailand to take "a child bride who was about 12 years old at the time." He provided no evidence.

To win the defamation case, Unsworth needs to show that Musk was negligent in publishing a falsehood that clearly identified the plaintiff and caused him harm. "Actual malice" on Musk's part does not need to be proven because the judge has deemed Unsworth a private individual rather than a public figure.

Unsworth is seeking unspecified damages for pain, suffering and emotional distress. The defence has resisted efforts to turn over financial records to show Musk's wealth, but has stipulated his net worth exceeds $20 billion.

A jury of five men and three women is weighing the case.

In an opening statement earlier in the day, lawyer Taylor Wilson, another member of Unsworth's legal team, said the tweet in question was more than a slip-up, and Musk had no business branding Unsworth a predator "in what should have been one of the proudest moments of his life."

Musk lawyer Alex Spiro countered that Unsworth did not act after the tweet like a man who suffered because of it.

"The plaintiff is saying he has been horribly damaged, and deserves money," Spiro said. "He doesn't."

Tweets in court

Although the case does not involve Tesla, Musk's Twitter habits have long been under close scrutiny, with investors and regulators expressing concerns about his tweets.

With 29.8 million followers, Musk's Twitter account is a major source of publicity for his Palo Alto, Calif.-based electric car company, which does not advertise.

His tweets have also previously landed him in court. 

Musk and Tesla reached a $40-million US settlement with the Securities and Exchange Commission last year on allegations he misled investors with a tweet declaring he had secured financing to buy out the electric car maker. He agreed in the settlement to have future tweets about the company screened.

He was forced back into court on accusations he violated that agreement by tweeting a misleading figure about how many cars Tesla would manufacture this year. The SEC sought to hold him in contempt of court, which led to a new agreement imposing tighter controls on Musk's tweets about the company.