The co-founder of Donald Trump’s beleaguered social media company has turned whistleblower, alleging the firm violated federal securities laws and that the former president pressured executives to hand over lucrative shares to his wife.

Will Wilkerson, a former Trump Media and Technology Group executive, has told the US government’s financial watchdog that the company’s bid to raise more than $1bn via an investment vehicle known as a special purpose acquisition company (Spac), relied on “fraudulent misrepresentations … in violation of federal securities laws.”

Trump Media and Technology Group is the company that launched Trump’s Truth Social platform after Twitter and Facebook banned the ex-president for his role in the deadly January 6 attack on the Capitol.

Wilkerson, who was sacked from his role as senior vice-president for operations last week after speaking to the Washington Post, filed a whistleblower complaint to the US Securities and Exchange Commission (SEC) in August. He backed his complaint with a cache of emails, documents, messages and audio recordings which detail a pattern of rancorous infighting, technical incompetence and power struggles inside Trump Media since its launch last year.

Among the emails is an exchange between Wilkerson and fellow co-founder Andy Litinsky, who was allegedly fired as payback for refusing to hand over some of his shares, worth millions of dollars, to former first lady Melania Trump, according to the Post. Trump had already been given 90% of the company’s shares in exchange for the use of his name and some minor involvement.

In the email provided to the SEC, Litinsky, who first met Trump in 2004 as a contestant on the TV show The Apprentice, said that Trump was “retaliating against me” by threatening to “‘blow up the company’ if his demands are not met”.

The SEC was already investigating the merger between Trump media and the Spac, Digital World Acquisition Corp, which has been on hold since last October due to civil and criminal investigations as well as lacklustre investor backing.

Wilkerson’s lawyers have said that he is cooperating with investigators at the SEC, and New York-based federal prosecutors are also looking into alleged criminality at Trump Media in relation to the merger which would have led to a $1.3bn cash injection. Digital World’s share price dived to under $18 on Friday from a high of $175.

Investors were promised more than 50 million users by 2024, but so far Trump, the main attraction on the platform, has less than 5 million followers – just a fraction of the 88 million he had on Twitter.

The whistleblower complaint was first reported by the Miami Herald, but Trump Media fired Wilkerson last Thursday, citing his “unauthorized disclosures” to the Post. His lawyer Phil Brewster described the move as “patent retaliation against a SEC whistleblower of the worst kind”.

Trump’s and the company’s legal woes – and desperate actions – are mounting as he contends with federal and state investigations in New York, Georgia and Washington DC over his business practices and his lies about being robbed victory during the 2020 presidential race.

Last month, New York attorney general Letitia James’s office sent a criminal referral to federal prosecutors in Manhattan and the IRS regarding multiple possible crimes including bank fraud uncovered. In a separate civil suit, the attorney general is seeking $250m in damages, alleging that Trump, three of his adult children, his business organization and others of submitting years of fraudulent financial statements.