Elon Musk’s attorney pressured a British cave explorer to apologize for criticizing Musk’s miniature submarine, in the third day of Vernon Unsworth’s defamation trial.

“Do you believe Mr Musk is so cold-hearted that he was sending over this sub with no regard for the children’s lives?” Bill Price asked Vernon Unsworth in a Los Angeles federal court on Thursday. “Are you willing to apologize to Mr Musk for saying that it was just a PR stunt?”

Unsworth, who brought suit against Musk after the Tesla and SpaceX chief referred to him as a “pedo guy” on Twitter, declined.

“My insult was to the tube and not to Mr Musk personally,” Unsworth said. “I’m not sure how I need to apologize. It was my opinion at the time and I stand by that opinion.”

After two days of testimony dominated by Musk’s global celebrity, the British cave explorer took center stage in Thursday’s proceedings. Unsworth had testified feelingly on Wednesday about the impact of being “branded a pedophile” by Musk’s tweets, which were published by an account with approximately 22 million followers. “I feel humiliated, ashamed, dirty … I was effectively given a life sentence without parole.”

But under cross-examination, Unsworth’s own words were placed under the microscope. Unsworth had mocked Musk’s submarine in an interview with CNN, deeming it a “PR stunt” and saying Musk should “stick his submarine where it hurts”.

Courtroom sketch shows Elon Musk during the trial in Los Angeles, California, on 4 December 2019. Photograph: Mona Shafer Edwards/Reuters

Additional questioning appeared designed to undercut Unsworth’s claim to have suffered emotional distress over Musk’s words. After it was established that Unsworth had not mentioned such distress in many thousands of text messages exchanged over months with a half-dozen friends, the 64-year-old said: “I very rarely talk to my friends about my emotional issues, certainly not in text messages. I bottle it up.”

Price also displayed a photo of Unsworth and other members of the British rescue team taken with Theresa May outside 10 Downing Street. “You would agree that the prime minister of England would not want to be seen with someone who is a pedophile?” Price asked.

In discussing his investiture as a member of the Order of the British Empire, Unsworth said that Prince William “suddenly mentioned the situation that existed with Mr Musk”. However, the judge prevented Unsworth from relaying what Prince William said about Musk.

On Tuesday, Unsworth had testified that the great honor of his MBE was clouded by his shame at the “pedo guy” smear, and said he only attended his investiture because his mother, partner and niece asked him to.

Further questions addressed Unsworth’s involvement with various film and book projects about the cave rescue. Unsworth said that he briefly engaged an agent and hoped to sell his story for a substantial sum, as others involved in the rescue have done, but none of the projects materialized.

Unsworth did assist with three book projects for free, including a children’s book, and was paid a total of £2,600 ($3,400) for appearing in two documentaries, he said. Unsworth works as a financial consultant and earns approximately £25,000 annually, he testified.

Dr Jim Jansen, a professor of computer science at Penn State university, provided expert testimony for the plaintiffs on the “level of online dissemination” of Musk’s “pedo guy” statement. Jansen testified that 490 articles had appeared on 361 websites in 33 countries about Musk’s remarks, based on searches limited to the English language and excluding articles about Unsworth’s litigation.

The jury also heard excerpts from a video deposition by Unsworth’s wife, Vanessa Unsworth. The couple have been living separate lives since around 2006 but remain married. Vanessa testified that her husband was “really devastated” by Musk’s remark and said she was “incredibly proud” of his actions in the cave rescue. Asked about Unsworth’s criticism of Musk, she said: “It is a comment that, as Brits, we do say: ‘Stick it where the sun doesn’t shine.’”

Musk’s defense attorneys did not call any witnesses. The defense asked the judge to decide the case on the law, arguing that “no reasonable jury could find for Unsworth on the basis of law”, which the judge refused to do.

The trial will continue on Friday morning with closing arguments and jury instructions, after which the jury will deliberate.

In his own testimony earlier this week, Musk, 48, apologized to Unsworth and said he did not believe the cave explorer was a pedophile.

He also dismissed the tweets as an “off the cuff” response to watching a replay of Unsworth’s CNN interview, at a time he felt overworked from running Tesla, which makes electric cars, and SpaceX, a rocket company that offered the mini-submarine.

To win his lawsuit, Unsworth needs to show Musk was negligent in publishing a falsehood that clearly identified him and caused him harm. He does not need to show that Musk acted with “actual malice”, which is much tougher to prove.

Reuters contributed reporting