Elon Musk is under investigation by federal authorities over his beleaguered bid to buy Twitter, according to a recent court filing from the social media company. Lawyers for Twitter, which is suing Musk for attempting to back out of a purchase agreement, said in an Oct. 6 filing that the billionaire was “under investigation by federal authorities for his conduct in connection with the acquisition of Twitter.” The company asked for access to documents that Musk had shared with investigators, saying they “bear upon key issues in this litigation.” Musk first started threatening to back out of the purchase agreement in May, claiming Twitter had been dishonest about the number of fake accounts on the platform. The Securities and Exchange Commission questioned Musk’s lawyers about these threats in June; Twitter sued the businessman in July. Musk agreed to buy the company again last week, putting the suit temporarily on hold. Delaware Chancery Court Chancellor Kathaleen St. Jude McCormick has given the parties until Oct. 28 to close the deal or resume trial.