Nikola Corp. founder and former Chairman Trevor Milton appears to have deleted his Twitter account days after resigning from the company’s board amid federal probes about allegations of deception.

An avid user of social media, Milton has been under pressure since a short seller accused him and his company of misrepresenting the capabilities of its vehicle prototypes and its technology. His Twitter account, which he once posted to frequently and publicly, had been silent and locked to unapproved viewers before apparently being disabled or deleted on Tuesday.

Milton’s Twitter handle -- @nikolatrevor -- brought up a webpage that says “This account doesn’t exist.”

Representatives for Milton and Nikola, from which he resigned on Sunday, were unavailable for immediate comment.

Shares of Nikola have collapsed in the wake of allegations Milton and Nikola mislead investors, which both have denied. Bloomberg reported last week the U.S. Securities and Exchange Commission is examining those claims, and the Department of Justice reportedly has launched its own probe.

The stock rose 3.4 per cent to close at US$28.51 on Tuesday but is down about 16 per cent since Nikola went public in a reverse merger on June 4. At one point the company’s market capitalization exceeded Ford Motor Co. amid a boom in electric-vehicle-maker shares.

Milton often used social media such as Twitter and Instagram to attack critics and boast about Nikola’s planned vehicles. On June 8, he tweeted that Nikola would soon start taking reservations for a battery-powered pickup dubbed the Badger -- Nikola’s first commercially available vehicle -- calling it “the most bad a-- zero emission truck.”

Milton tweeted a statement from Nikola on Sept. 20 explaining his decision to step down.

“Nikola is truly in my blood and always will be, and the focus should be on the company and its world-changing mission, not me,” Milton said in the statement. “So I made the difficult decision to approach the board and step aside.”

On Sept. 11, Milton made several ephemeral posts to his Instagram account, including one that revealed Nikola had contacted the SEC and held “formal talks” about the Hindenburg report. Later that evening, he posted an expletive-laden live video on Instagram addressing some of the claims in the short report and berating the report’s author, along with other critics of the company.

Milton’s Instagram account appears to still be active but has been made “private” in recent days, meaning Milton would need to accept a request to follow him.