Jeff Bezos, the chief executive of Amazon and the richest man in the world, published an extraordinarily personal blog post on Thursday that accused the owner of The National Enquirer of trying to blackmail him in order to stop an investigation into how the tabloid had obtained private messages and pictures sent between him and the woman he was seeing.

In the post, Mr. Bezos said The National Enquirer’s parent company, American Media Inc., was threatening to publish explicit pictures of him and the woman, Lauren Sanchez. He also named the chairman of A.M.I., David Pecker.

The following are excerpts from the blog post.

What does The Enquirer claim to have?

Mr. Bezos published an email he said was from Dylan Howard, the chief content officer of A.M.I. Mr. Howard provided details about the pictures the company claimed to have. The list begins with a “below the belt selfie” and describes nine other images, including:

• A full-length body selfie of Mr. Bezos wearing just a pair of tight black boxer-briefs or trunks, with his phone in his left hand — while wearing his wedding ring. • A selfie of Mr. Bezos fully clothed. • A full-length scantily clad body shot with short trunks.

What does The Enquirer want?

Mr. Bezos published an email he said was from Jon P. Fine, a lawyer for A.M.I., that included a list of demands. Some of those included:

1. A full and complete mutual release of all claims that American Media, on the one hand, and Jeff Bezos and Gavin de Becker (the “Bezos Parties”), on the other, may have against each other. 2. A public, mutually-agreed upon acknowledgment from the Bezos Parties, released through a mutually-agreeable news outlet, affirming that they have no knowledge or basis for suggesting that AM’s coverage was politically motivated or influenced by political forces, and an agreement that they will cease referring to such a possibility.

Is this politically motivated?

Mr. Bezos alludes to another potential motivation for A.M.I.’s blackmail threat: He owns The Washington Post.

The paper has investigated A.M.I.; reports on President Trump, a longtime friend of Mr. Pecker; and employed Jamal Khashoggi, a Saudi columnist killed by operatives from Saudi Arabia, where A.M.I. does lucrative business. The Post has reported extensively on Mr. Khashoggi’s killing.