But he said he couldn't 'get into it.'
Donald Trump said Tuesday he knows the identity of the author known as "Anonymous," the senior administration official who wrote an inside-the-White House account that painted the president as inept and dangerous.
Trump's claim comes as speculation has grown inside Washington about the identity of the official who penned the book "A Warning" as well as an eviscerating 2018 essay in The New York Times about the president's "misguided impulses"
"I know who it is," Trump told reporters. "I can't tell you that. ..We won't get into it."
In the book, published by the Hachette Book Group in November, the writer claims senior administration officials considered resigning as a group in 2018 in a "midnight self-massacre," but ultimately decided such an act would do more harm than good.
Ahead of the book's publication, the Justice Department sent a letter to Hachette and the writer's literary agency, raising questions over whether any confidentiality agreement had been violated and asking for information that could help reveal the author's identity.
Hachette responded by saying it would provide no additional information beyond calling the author a "current or former senior official."
Trump has pointed to the book to make the case that some in his administration, including Obama holdovers, are working to undermine his agenda.
White House press secretary Stephanie Grisham has dismissed the author as a "coward" and the content of the person's writings as "nothing but lies."
Trump did not say what if any steps he plans to take against the writer.
"People know it's a fraud," Trump added.