SEATTLE — Jeff Bezos’ security consultant accused the Saudi government of gaining unauthorized access to the Amazon chief executive’s phone, as part of an effort to harm the world’s richest man.

In an opinion article in The Daily Beast on Saturday, Gavin de Becker, Mr. Bezos’ security chief, alleged the Saudis wanted to hurt Mr. Bezos because he owns The Washington Post. The Post has aggressively reported on the murder of Jamal Khashoggi, one of its columnists, who was killed last year in Turkey. United States officials have concluded Mr. Khashoggi, who was critical of Saudi leaders, was killed on the orders of the Saudi crown prince, Mohammed bin Salman.

Mr. de Becker said he had turned over his findings about the Saudis and their role against Mr. Bezos to law enforcement.

“Our investigators and several experts concluded with high confidence that the Saudis had access to Bezos’ phone, and gained private information,” Mr. de Becker wrote.