The pair first clashed over Mr Musk's offer of a mini-submarine to help with the rescue.
Musk called Unsworth a "single white guy from England who's been travelling to or living in Thailand for 30 to 40 years", alleging that he had moved to Chiang Rai "for a child bride who was about 12 years old at the time".
"It isn't where you'd go for caves, but it is where you'd go for something else", Mr Musk wrote.
He suggested Pattaya and Chiang Rai were hotspots of the child sex industry and added: 'I ****ing hope he sues me'.
Image copyright Reuters Image caption Mr Unsworth, in orange, provided information for the rescue What is Unsworth's response? Musk deleted the tweets and apologized to Unsworth three days later. Tesla is reportedly asking for deposits of around £38,000, while the list price of the vehicle is set to start at £151,000 - although those figures are based on the announced USA pricing of the auto, no United Kingdom numbers have been confirmed yet.
"He seems to have a reckless indifference about the truth of these things".
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'This has been going since July and he has not produced a scintilla of evidence. "We feel very strongly that the record should be put straight".
BuzzFeed reportedly investigated the allegations against Unsworth but could not confirm any of them or where the allegations had come from.
Mr Unsworth, a financial broker, splits his time between the United Kingdom and Thailand. A price of around £151,000 makes it cheaper than any other auto in Tesla's relatively pricey range, but as bang for your buck goes, it'll probably be the best value supercar out there, with cars with comparable performance usually commanding a seven-figure pricetag. Musk had accused Vernon Unsworth of pedophilia after Unsworth rejected a Tesla-made submarine to aid in the rescue efforts.
Mr Unsworth did not take part in the dives but had previously explored the cave complex extensively. Their reporting has not yet turned up any evidence of a criminal record for Unsworth in the United Kingdom, while a Thai official said it was highly unlikely Unsworth, who has lived in Thailand on-and-off for years, would be granted a visa if there was evidence he was a child abuser.
'After deleting the initial accusation and tweeting an apology, Mr Musk has continued to republish his false and unsupportable accusation.
In July he shocked investors by announcing on Twitter that he had funding secured to take his auto firm Tesla private.
He also tweeted that he suffered from "great highs, awful lows and unrelenting stress".