LOS ANGELES — Amazon CEO Jeff Bezos said Thursday he was the target of “extortion and blackmail” by the publisher of the National Enquirer, which he said threatened to publish revealing personal photos of him unless he stopped investigating its acquisition of other private images and messages and unless he declared its coverage wasn’t politically motivated.

Bezos, who is also owner of The Washington Post, detailed his interactions with American Media Inc. in an extraordinary blog post Thursday on the Medium.com website.

After the tabloid published a story about his extramarital affair last month, Bezos ordered a team of private investigators to get to the bottom of how the Enquirer obtained risque texts between the executive and former TV anchor Lauren Sanchez. Since then, there’s been a public relations battle.

Bezos’ investigators have suggested the Enquirer’s coverage of his affair was politically motivated. Bezos has been the target of criticism from President Donald Trump over the Post’s critical coverage of the White House, and AMI has admitted that it engaged in what’s known as “catch-and-kill” practices to help Trump become president.

That admission was part of a deal between AMI and federal prosecutors, who agreed to not pursue charges against the company for secretly assisting Trump’s campaign by paying $150,000 to a Playboy model for the rights to her story about an alleged affair with the then-candidate. The company then intentionally suppressed the story until after the 2016 election.

Several days ago, someone at AMI told Bezos’ team that the company’s CEO David Pecker was “apoplectic” about Bezos’ investigation, Bezos said. AMI later approached Bezos’ representatives with an offer.

“They said they had more of my text messages and photos that they would publish if we didn’t stop our investigation,” Bezos wrote in the post.

Bezos wrote that this week, the tabloid’s editor, Dylan Howard, emailed an attorney for Bezos’ longtime security consultant to describe photos the Enquirer “obtained during our newsgathering.” The photos include a “below the belt selfie” of Bezos, photos of him in tight boxer-briefs and wearing only a towel, and several revealing photos of Sanchez, according to the email Bezos released in his blog post.

According to the emails, an attorney for AMI offered a formal deal Wednesday: The tabloid wouldn’t post the photos if Bezos and his investigators would release a public statement “affirming that they have no knowledge or basis” to suggest the Enquirer’s coverage was “politically motivated or influenced by political forces.”

Bezos said he decided to publish the emails sent to his team “rather than capitulate to extortion and blackmail,” despite the “personal cost and embarrassment they threaten.”

AMI didn’t demand any money from Bezos, the world’s richest person – only that he call off his investigation and issue a statement saying the coverage wasn’t political.

A spokesman and an attorney for AMI did not immediately respond to messages seeking comment.

In its Jan. 9 story, the Enquirer reported that Bezos sent “sleazy text messages and gushing love notes” to Sanchez, months before Bezos announced he was splitting up with his wife, MacKenzie. Reporters for the Enquirer followed Bezos and Sanchez “across five states and 40,000 miles” and “tailed them in private jets, swanky limos, helicopter rides, romantic hikes, five-star hotel hideaways, intimate dinner dates and ‘quality time’ in hidden love nests,” the tabloid said in its story. The story carries the bylines of Howard and two reporters.

After the story ran, Bezos ordered his longtime security consultant, Gavin de Becker, to lead the probe into how the Enquirer obtained the lewd text messages. His private investigators have concluded that Bezos’ phone wasn’t hacked. Instead, they’ve been focusing on Sanchez’s brother, according to a person familiar with the matter.

De Becker and his team suspect Michael Sanchez, a talent manager who touts his support of Trump and is an acquaintance of Trump allies Roger Stone and Carter Page, may have provided the information to the Enquirer, the person said. The person wasn’t authorized to discuss the matter publicly and spoke on condition of anonymity.

Sanchez, who is also his sister’s manager, has declined to speak with The Associated Press on the record and did not immediately respond to an email seeking comment Thursday. In a tweet, he said de Becker “spreads fake, unhinged conservative conspiracy theories” and “‘dog whistle’ smears.”

AMI was a focus of the federal investigation into campaign finance violations by Trump’s former personal attorney and fixer, Michael Cohen. Cohen pleaded guilty to several federal crimes and admitted that he had made a deal, on Trump’s behalf, in which the Enquirer helped Trump’s presidential bid by paying $150,000 to former Playboy playmate Karen McDougal to buy and bury her story.

In September, the Justice Department agreed to a non-prosecution agreement with AMI, which requires the company and some top executives, including CEO David Pecker and Howard, to cooperate with authorities.

De Becker is now trying to find a way that federal prosecutors in Manhattan — where the non-prosecution agreement was signed — could investigate the text message scandal, the person familiar with the matter said, though it wasn’t immediately clear what, if any, crime the prosecutors would be asked to look into.