Elon Musk spent more than $50,000 digging into the personal life of British expat and Thai caver Vern Unsworth in summer 2018 in an effort to substantiate the claim that he was a "pedo guy." Musk revealed the spending in his latest response to a defamation lawsuit Unsworth filed against him last year.

Initially, Musk's investigator turned up some seemingly damning information about Unsworth, including a claim that Unsworth began dating his wife when she was around 12 years old. However, further investigation failed to confirm this claim, with the investigator finding she was actually around 18 years old when the couple met. (The wife, Woranan Ratrawiphukkunand, later told UK newspapers she was 33 when they met.)

But Musk argues that it doesn't matter, legally speaking, if his claims about Unsworth were actually true. What matters is that Musk believed the claims were true at the time he repeated them to BuzzFeed reporter Ryan Mac.

Musk also blames Mac for publishing the email even though Musk had marked it as "off the record." Ultimately, Musk argues, he shouldn't be held legally responsible for false claims about Unsworth winding up in the media.

At the same time, Musk argues that his initial statement about Unsworth—that he was a "pedo guy"—wasn't intended to be a factual claim at all. Instead, he says, it was intended to be taken as a generic insult.

“Sorry, pedo guy, you really did ask for it”

The bizarre legal battle began last July when Musk had a team of SpaceX engineers construct a miniature submarine to help rescue kids stranded in a cave in Thailand. Musk thought two divers could carry the craft between them as they exited the cave.

Ultimately, Thai officials rescued the boys without Musk's help. Unsworth, a cave expert who helped plan the rescue effort, went on CNN to talk about the effort. Asked about Musk's project, he described it as a publicity stunt that had "absolutely no chance of working." He encouraged Musk to "stick his submarine where it hurts."

On Twitter, Musk vowed to prove Unsworth wrong by demonstrating that the submarine could be squeezed through the cave's narrowest passages. "Sorry pedo guy, you really did ask for it," he tweeted. When pressed on the "pedo" charge, Musk added "Bet ya a signed dollar it's true."

Musk apologized a few days later and deleted his tweets. But he didn't seem all that sorry. "You don't think it's strange he hasn't sued me?" he asked on Twitter in late August.

In July, Musk asked the head of his family office, Jared Birchall, to retain a private investigator to dig into Unsworth's personal life. Birchall says that, in a series of phone calls, investigator James Howard told him that Unsworth's wife was 11 or 12 at the time the couple started dating. In a subsequent written report, Howard stated that Unsworth's wife was actually around 18 at the time they met.

Musk says his claims about Unsworth living in Pattaya Beach also came from Howard. In a report, Howard wrote that he was trying to verify that Unsworth had moved to a part of Thailand renowned for sex trafficking—which would bolster the view that he was a "sexpat." Howard explained that a sexpat is someone who "whore-mongers his way through the go-go bars of Thailand." He reported that Unsworth was an "unpopular loner" and that some other expats found Unsworth "creepy."

Around the same time, Buzzfeed reporter Ryan Mac asked Musk for comment about his dispute with Unsworth. Musk responded with accusations that were apparently drawn from Howard's findings:

He's an old, single white guy from England who has been traveling to or living in Thailand for 30 or 40 years, mostly Pattaya Beach, until moving to Chiang Rai for a child bride who was about 12 years old at the time. There's only one reason people go to Pattaya Beach. It isn't where you go for caves, but it is where you'd go for something else. Chiang Rai is renowned for child sex-trafficking.

Musk wrote "Off the record" at the top of the email, apparently expecting that would obligate Mac not to publish his comments. But Mac hadn't promised Musk to keep his email confidential, so he published it in full.

Musk blames Mac for publishing the emails

The Buzzfeed email probably represents Unsworth's strongest chance of winning the lawsuit, since it contains specific, factual claims about Unsworth—especially the claim that he moved to Chiang Rai for a 12-year-old bride. But Musk argues that there are two reasons he shouldn't be held responsible for that apparently false claim.

Musk "believed the investigator to be credible" and didn't entertain serious doubts about his findings, Musk says. Musk argues that paying $50,000 for Howard's work is a sign that Musk believed he was getting high-quality information—even if the information ultimately turned out to be faulty.

Second, Musk didn't expect Mac to publish the emails. Musk says he believed that journalistic ethics required Mac not to publish emails that were marked as off the record (many journalists disagree). He also believed that Mac would verify the salacious information before disseminating it to a broad audience.

Finally, Musk argues that he is on solid legal ground because Unsworth was a public figure in the context of the Thai cave rescue debate. American courts have set a high bar in defamation cases involving public figure: a plaintiff must show that a defendant showed "actual malice" in the publication of defamatory information. Mere sloppiness isn't enough—under this standard, if Unsworth is held to be a public figure he would have to show that Musk either deliberately printed false information or showed reckless disregard for the truth.

Musk has sought to depose Mac for the case, but Buzzfeed has objected, arguing that Mac has already supplied both parties all relevant information about the case. Buzzfeed argues that Musk is trying to harass Mac and punish him for publishing Musk's emails.

Musk: “Bet ya a signed dollar” was actually an expression of uncertainty

Musk claims that he didn't mean for people to take his "pedo guy" insult literally. He claims that this was a schoolyard taunt he heard growing up in South Africa and that it was a generic insult rather than a factual claim about the subject engaging in pedophilia.

A tricky thing about this claim, however, is that Musk followed it up by tweeting "bet ya a signed dollar it's true"—which seems like confirmation that he meant it to be taken literally.

But Musk argues that's wrong. Rather, Musk's lawyers write, it was a "flippant comment" that Musk didn't intend to be taken seriously.

"By proposing such an insubstantial wager, Musk was not taking a strong position as to whether his statements were true, or even capable of being proven true," his lawyers write. Rather, they claim Musk meant to covey "obviously I'm not certain about this."

Hence, Musk's lawyers conclude, "there is no evidence that Musk intended or believed that his July 15 tweets, that Unsworth was "pedo guy'" would be interpreted as fact.

There's an obvious tension between the two halves of Musk's argument. On the one hand, he argues that his early tweets—that Unsworth was a "pedo guy" and Musk would "bet ya a signed dollar" it was true—was meant to be merely generic insults, not factual claims. But if that's true then why would Musk spend $50,000 to substantiate claims that weren't intended to be taken literally?

On the flip side, the fact that Musk first tweeted about Unsworth being a "pedo guy" before launching his investigation of Unsworth could make it easier for Unsworth to argue that Musk had shown reckless disregard for the truth.

Ken White, a First Amendment lawyer who runs the Popehat blog, argues that Musk's arguments could ultimately prevail, but it won't be a quick victory. His argument "isn't the best fit for a summary judgment motion, which requires that there be no material disputed facts," White wrote in an email to Ars. There are plenty of disputed facts here. So we can expect this case to drag on for some time to come.