SEC officials investigating Elon Musk for his takeover of Twitter appear to be growing impatient with his legal antics. The two sides have been embroiled in a dispute over Musk’s refusal to testify in the investigation. Now, in a new filing, the SEC is accusing Musk of trying to “misrepresent” the regulator’s investigation. “Musk continues to misrepresent the true scope of this investigation — his only hope is to establish that the SEC is not pursuing relevant evidence,” the SEC wrote in a court filing.

The SEC is investigating Musk for his delayed disclosure of his holdings at Twitter, which was then a publicly traded company. Regulator Musk last year in an attempt to compel him to testify in the investigation. The SEC said it was investigating “among other things, potential violations of various provisions of the federal securities laws in connection with” his purchase of Twitter stock and “Twitter-related SEC filings.” A federal judge ordered Musk to comply with the subpoena and schedule an interview.

That testimony apparently hasn’t been given yet, with the SEC accusing Musk of using “manipulation” to stall the investigation. The regulator further noted that while Musk’s legal team claimed the probe was “an open-ended investigation into an alleged days-late SEC filing,” that “SEC staff repeatedly informed Musk that it was false.”

Musk, according to the SEC, is also under investigation for securities fraud. “This investigation also addresses potential securities fraud in violation of Section 10(b) of the Securities Exchange Act … related to, among other things, Musk’s public statements regarding his acquisition of Twitter,” the SEC said.

Notably, the filing also mentions the recently published y of Musk written by Walter Isaacson, which contains “newly released evidence,” according to the SEC. “Three days before he appeared for the deposition he did not attend, his biography dated September 2023 was released,” the SEC wrote. “This book provides important new information related to the SEC’s investigation.”

It’s also not the first time Isaacson’s account of the Twitter takeover has landed Musk in hot water. A group suing Musk for unpaid damages also cites a passage from the book in its lawsuit.

X did not immediately respond to a request for comment.