Elon Musk is being investigated by federal authorities over his conduct in his $44bn (£39bn) takeover deal of Twitter, the social media company has said in a court filing.

The world’s richest man recently announced he would go ahead with purchasing the platform for the huge sum, following months of legal battles.

Twitter, which sued the Tesla boss in July to force him to close the deal, said Mr Musk’s attorneys had claimed “investigative privilege” when refusing to hand over documents it had requested.

In late September, Mr Musk’s legal team had provided a “privilege log”, which identified documents that needed to be withheld, according to the social media giant.

The log referred to drafts of an email to the US Securities and Exchange Commission (SEC) and a slide presentation to the Federal Trade Commission.

While the court filing, which was released on Thursday, said the billionaire was under investigation, it did not explain why.

Instead, it asked for a judge to order Mr Musk’s attorneys to hand over the documents.

The filing was made on 6 October – the same day the Delaware judge paused litigation between the two sides after Mr Musk announced he would proceed with the deal.

Read more: Elon Musk’s Twitter deal is back on – but will he back out for a second time?

“This game of hide the ball must end,” Twitter said in the document.

One of Mr Musk’s attorneys, Alex Spiro, said the filing was a “misdirection” by the company, adding: “It is Twitter’s executives that are under federal investigation.”

Twitter declined to comment on Mr Spiro’s statement.

This is not the first time Mr Musk has been questioned, with the SEC previously asking him about comments he made regarding the Twitter acquisition.

In April, the SEC asked Mr Musk whether the disclosure of his 9% Twitter stake was late and why it indicated that he
intended to be a passive shareholder.

He later refiled to show he was an active investor.