Mr. Bezos, who owns The Washington Post, suggested that the Saudis had been angry over the newspaper’s coverage of the killing of Jamal Khashoggi, a Saudi dissident and columnist for The Post who was murdered by Saudi assassins weeks after writing critically of Crown Prince Mohammed bin Salman for the paper. Mr. Bezos also cited the wooing of Prince Mohammed by David J. Pecker, the chief executive of American Media, the publisher of The Enquirer, who was seeking Saudi investment in the company.

Last month, the results of a forensic analysis commissioned by Mr. Bezos became public. It concluded with “medium to high confidence” that the Amazon founder’s iPhone X had been hacked after he received a video from a WhatsApp message sent to him from an account reportedly belonging to the Saudi crown prince, with whom the billionaire had swapped contacts at a Los Angeles dinner. The analysis did not reveal a Saudi connection to the materials obtained by The Enquirer.

American Media said in a statement last month that Mr. Sanchez was the “single source” for the exposé.

According to an October 2018 contract reviewed by The New York Times, Mr. Sanchez granted American Media the right to publish and license text messages and photographs “documenting an affair between Jeff Bezos and Lauren Sanchez” in exchange for $200,000. In his lawsuit, Mr. Sanchez did not address whether he had provided text messages or photographs — other than his denial of supplying nude pictures — or whether he was compensated by the tabloid.

When federal agents and prosecutors examined allegations of wrongdoing in connection with The Enquirer’s handling of the story, American Media gave them evidence showing that Mr. Sanchez had obtained text messages and photos of Mr. Bezos from his sister, four people with knowledge of the matter told The Times.

In his blog post last year, Mr. Bezos quoted emails sent to Mr. de Becker’s lawyer by an American Media lawyer and a company executive, who wrote that “the photos obtained during our news gathering” included a nude “below-the-belt selfie.” American Media said in the emails that it would refrain from publishing the photographs if Mr. Bezos said publicly that he believed the exposé was not politically motivated. (The Enquirer had been a booster of President Trump, who was at odds with Mr. Bezos.)