American Jewish billionaire and casino magnate Sheldon Adelson was reportedly questioned by Israeli investigators for three hours on Thursday in a case relating to Prime Minister Benjamin Netanyahu's attempted negotiations with arch-foe newspaper owner Arnon Mozes.

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The so-called "Case 2000" involves suspicions that Netanyahu promised to rein in the Adelson owned Israel Hayom, which is heavily pro-Netanyahu, in exchange for getting more favorable coverage in Mozes's Yedioth Ahronoth newspaper.

His wife Miriam is also due to be questioned by investigators. Police believe that Miriam's testimony may be even more significant because she is more active in the newspaper.

Adelson was expected to be asked by police if he had authorized Netanyahu to conduct any kind of negotiations with Mozes, and whether he knew about their conversations, the transcripts of which were published in January.

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Adelson was also to be asked about the degree of Netanyahu’s involvement with the workings of the newspaper, and whether the premier had ever been authorized to negotiate advertising rates.

In January, Justice Ministry officials said Case 2000 would take time since it required taking testimony from witnesses abroad as well as in Israel.