Elon Musk apologized to British diver Vern Unsworth after the Tesla Inc. (TSLA.O) chief executive officer labelled him a pedophile earlier this week in a now-deleted Twitter post.

“My words were spoken in anger after Mr. Unsworth said several untruths & suggested I engage in a sexual act with the mini-sub,” Musk, 47, said on Twitter in response to another user. “Nonetheless, his actions against me do not justify my actions against him, and for that I apologize to Mr. Unsworth and to the companies I represent as leader.”

The latest controversy to cloud Musk came after Unsworth, who played a key role in organizing the rescue of 12 boys and their soccer coach from a flooded Thai cave this month, dismissed the billionaire’s offer to provide a small submarine for the operation as a “PR stunt.” Musk retorted by calling him a pedophile, after which Tesla’s shares declined 2.8 per cent on Monday. The stock recovered on Tuesday.

Musk has a history of controversial outbursts, sparring with critics and investors betting against his company. Gene Munster, a managing partner at venture-capital firm Loup Ventures and one of the company’s biggest bulls, urged Musk to cool down, saying his conduct in the last six months has been concerning and is shaking investor confidence.

After Tesla shares fell 22 per cent in March — the steepest monthly drop in more than seven years — Musk jokingly tweeted on April Fools’ Day that the company had gone bankrupt. The following week, he hung up on the chairman of the National Transportation Safety Board who called to tell him the agency was booting Tesla representatives from the investigation of a fatal crash involving a Model X driver. The company had published a series of blog posts that cast blame on the deceased driver.

In May, Musk cut off analysts’ queries about the company’s capital requirements and orders for the Model 3 sedan during a conference call, calling them “boring, bonehead questions,” that led to a sharp decline in Tesla’s stock. Earlier this month, Musk said in an interview with Bloomberg Businessweek that he would engage with his detractors on Twitter less often.

James Anderson, a partner and portfolio manager at Baillie Gifford & Co., last week called for “peace and execution” and urged Musk to focus on the company’s core tasks, while Munster said Musk’s "behaviour is fuelling an unhelpful perception" of his leadership.

"The fault is mine and mine alone," Musk said on Wednesday, referring to his comments to the British cave diver.