Hebrew-language media reported earlier on Thursday that the CEO of Walla, Ilan Yeshua, recorded the website's owner Elovitch ordering him to slant coverage in favor of Netanyahu and his family.
Netanyahu, who insists he has done nothing wrong, has faced corruption allegations periodically nearly since first becoming prime minister in 1996. Filber's change of heart could leave the tough-talking Netanyahu at his most vulnerable yet, with one critic writing him off as a "political corpse".
Another article at Haaretz details the basis of the suspicions that Netanyahu meddled in Israeli media outlets, among them television, internet, radio and printed press, and pushed through a bill that retroactively legalized the split of a Elovitch-owned television station.
"It was like watching a police vehicle chase in pursuit of a robber on one of America's endless highways", columnist Sima Kadmon wrote in Wednesday's Yedioth Ahronoth. Under the deal, Filber, who formerly served as director general of the Communications Ministry under Netanyahu, will not serve jail time. The ministry ruled or weighed in on a number of key regulatory decisions that provided enormous financial benefits to Bezeq and its controlling shareholder, Shaul Elovitch.
If Netanyahu stepped down as party leader, according to the poll, Likud would still win 26 seats. The process could take months.
In one he is suspected of bribery over gifts, which police say were worth almost $300,000, that he received from wealthy businessmen.
Filber has already told police he personally did not gain in any way by carrying out instructions, as the state is relying on his testimony to build its case against PM Netanyahu.
Through a spokesman, Netanyahu responded: "It never happened".
In another case announced this week, two Netanyahu allies are alleged to have offered a judge promotion in exchange for dropping a case against the premier's wife.
As part of the agreement made late Tuesday night, Filber offered police a detailed account of everything he knows about Netanyahu's part in the so-called Case 4000, as well as others involved in the affair. And this week, a new case emerged that threatens to be the most damaging of all, after one of his closest confidants agreed to testify against him in an influence-peddling scandal.
Israeli police have sent a recommendation to state prosecutors and the attorney general to indict Prime Minister Benjamin Netanyahu on criminal charges in two corruption cases.
The Gallup organization in a report issued late Wednesday evening found that prior to the corruption allegations, slightly more than half of Israelis, or 52 percent, said in 2017 that they approved of how Netanyahu was handling his job as prime minister.
Adding to the prime minister's woes, however, Filber is not the first former ally to have turned against Netanyahu.