British diver and cave explorer Vernon Unsworth has said he is considering legal action against SpaceX and Tesla Chief Executive Officer Elon Musk for calling him a “pedo”, or paedophile. Musk on Sunday criticised Unsworth, who was instrumental in saving the lives of 12 schoolboys and their football coach who were marooned in a cave in Thailand for more than 10 days.

Musk had offered to build a mini-submarine to rescue the boys, following it up with a visit to the cave complex, a move that Unsworth labelled a “publicity stunt” in an interview with CNN on Sunday. Unsworth said the mini-submarine was “not practical” for the rescue operation. The 63-year-old lives in Thailand, and his knowledge of the cave complex played an important role in finding the missing boys. He has since been hailed as a hero.

On Twitter on Sunday, Musk said he would build the mini-submarine to prove that it would have been successful. In the same tweet, he also called Unsworth “a pedo guy”. When another user queried why Musk was “calling the guy who found the children a pedo”, he tweeted, “Bet ya a signed dollar it’s true.” The tweets have since been deleted.

Speaking to reporters on Monday outside the cave complex, Unsworth said the baseless comments were an attack on the entire rescue crew. Asked if he would consider legal action against Musk, Unsworth said, “Yes, it’s not finished.”

Unsworth said he had saved copies of Musk’s tweets. “I have a lot of support from people around the world astonished by his unfounded comments. I don’t know the guy, never met the guy, and don’t want to meet the guy,” he said.

In an email response to The Guardian, James Anderson, a partner at Baillie Gifford, Tesla’s fourth-largest shareholder, said, “I intend to convey my – predictable I trust – feelings to the company tomorrow.”

The schoolboys and their coach, part of a football team, were trapped at the Tham Luang cave complex in Chiang Rai. After a joint international operation commenced on July 5, all 13 were brought out to safety.