A confidant of Israeli Prime Minister Benjamin Netanyahu has agreed to testify for the state in one of several probes against the long-serving premier. Shlomo Filber elected to turn state witness in what may pose a serious threat to Netanyahu’s political survival, local media said. Filber’s decision to testify against his former boss is a dramatic turn for Netanyahu, whose inner circle had so far seemed watertight. 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”. A spokesman for the police fraud squad declined to comment. Filber’s lawyer was not immediately available to confirm that a deal had been reached. The development has also fueled speculation that Netanyahu, 68, will call a snap election to try to stall legal proceedings during the campaign and rally his right-wing power base behind him. The prime minister denies all the allegations against him and has said he will seek a fifth term in office in a national ballot due in late 2019. So far, partners in his governing coalition have stood by him, showing little appetite for bringing down the government over the affairs and risking an early poll. Filber, a personal appointment of Netanyahu’s to head the Communications Ministry, was arrested this week along with top executives at Bezeq Telecom, Israel’s largest telecommunications company. In unsourced reports, Israeli media said Filber has now agreed to testify for the state in the case, providing evidence likely to complicate Netanyahu’s battle to overcome his legal crisis. Police suspect Bezeq received regulatory benefits, and in return, Netanyahu enjoyed favorable media coverage on a popular news website controlled by Bezeq’s former chairman. Bezeq executives have denied the allegations. Netanyahu, who has led Israel periodically for 12 years since 1996, is awaiting a decision by the attorney general on whether to indict him in two other cases as police recommended last week. Polls before Filber’s decision suggested Netanyahu would just about survive if an election was held now, despite widespread suspicion against him. A survey published on February 14 showed that almost half of Israel’s electorate believe police allegations of bribery against Netanyahu, while 25 percent said they believed Netanyahu’s denials. The remainder said they did not know whom to believe. But when people were asked whether he should remain in office or temporarily step aside, 49 percent said he should stay put, while 43 percent that he should step down temporarily Netanyahu posted an opinion poll commissioned by Likud on Facebook on Wednesday that showed that his party would boost its representation in the 120-member parliament from 30 seats to 34 if elections were held now. Still, the string of accusations appears to be taking its toll. Senior cabinet ministers from his ruling Likud party, who until just recently have marched out dutifully to defend him, have largely gone silent. Netanyahu himself appeared ashen in a video released late Tuesday calling the claims "total madness." “But the more they afflicted them, the more they multiplied and grew,” Netanyahu, who has said he is a victim of a political witch hunt, wrote in the posting, quoting Exodus 1:12. But political commentator Yossi Verter, writing in Israel’s left-wing Haaretz, a newspaper highly critical of Netanyahu and his policies, described him as a “political corpse” and predicted his own party would turn against him. “He is likely to call early elections in the next few months. But it’s unlikely that he’ll still be head of the Likud party when they happen, even less likely that he would win them, and exceedingly unlikely that he’d be able to form a coalition with conviction and jail time staring him in the face,” Verter wrote. Other leading columnists suggested that if Filber told all he knew, Netanyahu was probably more worried about avoiding prison than staying in office. "When so many dark clouds accumulate in the sky, the chances of rain increase," wrote Nahum Barnea in Yediot Ahronot. "His appearance lent the fight he is waging the dimensions of a Shakespearean tragedy. This isnt the end. It isnt even the beginning of the end. But it cannot have a different end." Filber is one of the closest people to Netanyahu, a loyal aide dating back to when Netanyahu first took office in 1996. Netanyahus former chief of staff Ari Harow has also signed a state witness settlement in which he agreed to testify against his former mentor. The collapse of Netanyahus inner circle has spawned rampant speculation that he may step down in return for a deal that offers him amnesty. On Tuesday, police alleged that Netanyahu’s former spokesman tried to bribe a judge to drop a fraud case against Netanyahu’s wife. The same associate is also a suspect in the Bezeq investigation.