NBC News chairman Andy Lack sent a letter to staffers with the network Wednesday that took issue with reporting in Ronan Farrow’s upcoming book, “Catch and Kill.”

In the book, Lauer -- whom NBC News fired for sexual misconduct in 2017 -- was accused of new sex crimes in graphic detail, according to Variety, which reported that the bombshell claims would be included in Farrow’s exposé. Fox News has not seen a copy of the closely guarded book, which is set to be released Oct. 15. Lauer denied the graphic rape claim in a strongly worded letter that his lawyer provided to Fox News on Wednesday, in which the former “Today” co-host said he initially was quiet for the sake of his children -- but will now defend himself.

“Matt Lauer’s conduct was appalling, horrific and reprehensible, as we said at the time. That’s why he was fired within 24 hours of us first learning of the complaint. Our hearts break again for our colleague,” NBC News said in a statement that was read on air.

However, in a letter sent to staff, Lack took issue with Farrow’s claims the network -- which employed him at the time -- attempted to stop him from looking into disgraced Hollywood mogul Harvey Weinstein.

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“In addition to his reporting on Lauer, Farrow’s new book also includes his telling of the NBC News investigation of Harvey Weinstein,” Lack wrote in the memo, obtained by Fox News.

“As you know, our news organization is filled with dedicated, professional journalists, including some of the best and most experienced investigative reporters, as well as others who support our reporting with exceptional talent, integrity and decency.

“It disappoints me to say that even with passage of time, Farrow’s account has become neither more accurate, nor more respectful of the dedicated colleagues he worked with here at NBC News. He uses a variety of tactics to paint a fundamentally untrue picture.”

Lack continued: “Here are the essential and indisputable facts:NBC News assigned the Harvey Weinstein story to Ronan, we completely supported it over many months with resources -- both financial and editorial.

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“After seven months, without one victim or witness on the record, he simply didn’t have a story that met our standard for broadcast nor that of any major news organization.

“Not willing to accept that standard and not wanting to get beaten by the New York Times, he asked to take his story to an outlet he claimed was ready to publish right away. Reluctantly, we allowed him to go ahead. Fifty-three days later, and five days after the New York Times did indeed break the story, he published an article at the New Yorker that bore little resemblance to the reporting he had while at NBC News.”

After listing some of the sexual scandals covered by the network, Lack wrapped up the note to staff.

“To get across the finish line on big stories like these takes exceptional work, collaboration, patience, and a commitment to a set of standards and practices that ultimately lends our work great credibility,” he wrote.

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“If you have any questions about the journalistic decisions that were made, please don’t hesitate to ask.”

Wednesday’s statement was not the first time Farrow and Lack have disagreed on how the award-winning journalist viewed his freedom to report on Weinstein while with NBC News.

Last year, Farrow fired back at NBC saying the news division produced “numerous false or misleading statements” when defending the Peacock Network’s handling of his reporting on Weinstein.

Farrow’s statement at the time came after Lack released a 10-page memo, complete with a cover letter and table of contents, addressing allegations by a former NBC News producer -- who was working with Farrow on the Weinstein probe -- that they were ordered to kill the report following directions from “the very highest levels at NBC.”

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“I’ve avoided commenting on the specifics of NBC’s role in the Weinstein story to keep the focus on the women and their allegations. But executives there have now produced a memo that contains numerous false or misleading statements, so I’ll say briefly: their list of sources is incomplete and omits women who were either identified in the NBC story or offered to be,” Farrow wrote.

Lack’s memo fought back against allegations that he tried to kill the story, labeling talk about the network’s handling of the report "an unusual situation for a news division."