Donald Trump accused Mark Zuckerberg of orchestrating a “plot” against him in the 2020 election, warning the Meta CEO that he will end up in jail if he “does anything illegal this time,” according to an except of a new book by the former president reported by Politico on Wednesday.

The book, titled “Save America,” is due to be released Sept. 3. It claims to offer “an unparalleled look” into Trump’s first presidential term and also lay out his vision for the future of the country.

In addition to touting his accomplishments, though, the book appears to delve into some of the former president’s grievances, including with Zuckerberg. Trump took aim at the tech executive and his over $400 million investment in election infrastructure amid the pandemic through the Chan Zuckerberg Initiative, the nonprofit he co-founded with his wife, Priscilla Chan, to suggest Zuckerberg sought to interfere in the past presidential election.

He “would come to the Oval Office to see me,” Trump wrote of Zuckerberg, according to Politico. “He would bring his very nice wife to dinners, be as nice as anyone could be, while always plotting to install shameful Lock Boxes in a true PLOT AGAINST THE PRESIDENT.”

Trump claimed that Zuckerberg “steered” Facebook against him, threatening to throw him behind bars if he takes similar action in the future.

“We are watching him closely, and if he does anything illegal this time he will spend the rest of his life in prison — as will others who cheat in the 2024 Presidential Election,” Trump wrote.

Zuckerberg has so far not commented on Trump’s claims.

The book also reportedly features a photo of the former president and Zuckerberg meeting at the White House, though it’s unclear when the visit took place, Politico reported.

Meanwhile, on Monday, Zuckerberg sent a letter addressed to Rep. Jim Jordan (R-Ohio), the chair of the House Judiciary Committee, in which he accused senior officials from the Biden administration of pressuring his company to “censor” posts related to the COVID-19 pandemic.

Zuckerberg said the government’s actions were “wrong” and said he would push back against similar efforts in the future. He also expressed regret about temporarily limiting the reach of a New York Post story referencing corruption allegations concerning Hunter Biden, President Joe Biden’s son.

In the letter, Zuckerberg vowed to not make any spending this election cycle, saying his investment in election infrastructure in the past presidential election were misconstrued.

“My goal is to be neutral and not play a role one way or another or to even appear to be playing a role,” he wrote.

The message was celebrated by House Republicans on the Judiciary Committee as a “big win for free speech,” saying every American ought to read it.

Trump also sought to capitalize on Zuckerberg’s letter, sending a fundraising email to his supporters, writing: “interference like this is worth billions.”

Earlier this summer, Zuckerberg praised Trump’s reaction to his attempted assassination during a Butler, Pennsylvania, rally, telling Bloomberg it was “one of the most badass things” he’s seen in his life.