The Department of Justice really wants to know who the anonymous author of A Warning is.

So does everybody else, of course. The author of the book, who claims to be a senior official in President Trump’s administration and who is sharply critical of Trump’s performance in the White House, has kept their identity a closely guarded secret.

Assistant Attorney General Joseph H. Hunt sent a letter to the author’s publisher and agents asking for proof that they didn’t sign a nondisclosure agreement with the government, the Washington Post reports.

Publisher Hachette and creative agency Javelin responded with a resounding “no.”

Hachette general counsel Carol Ross wrote back, “Hachette has … made a commitment of confidentiality to Anonymous and we intend to honor that commitment … Hachette respectfully declines to provide you with the information your letter seeks.”

Publishers Weekly reports that Javelin was similarly dismissive of Hunt’s request.

“Our author knows that the President is determined to unmask whistleblowers who may be in his midst. That’s one of the reasons A Warning was written,” the agency responded. “But we support the publisher in its resolve that the administration’s effort to intimidate and expose the senior official who has seen misconduct at the highest levels will not prevent this book from moving forward.”

A Warning, which as of Tuesday morning was the No. 1 bestselling book on Amazon, is slated for publication by Hachette imprint Twelve on Nov. 19.

Michael Schaub is an Austin, Texas-based journalist and regular contributor to NPR.