* One probe focuses on Israeli communications group
* Another investigation looks at suspected judge-bribing
* Police have recommended Netanyahu indictment in two other cases
JERUSALEM, Feb 20 (Reuters) - Israeli police alleged on Tuesday that Benjamin Netanyahu's former spokesman tried to bribe a judge to drop a fraud case against Netanyahu's wife, the latest corruption investigation encircling the long-serving prime minister.
The new bribery case was one of two revealed on Tuesday involving the same former spokesman, a close Netanyahu confidant. Police also named him as someone they had arrested two days earlier in a separate case involving allegations of corruption at Israel's biggest telecoms company.
The rightwing leader, in office for 12 years since 1996, has seen his dominance of Israeli politics threatened by corruption investigations since police recommended a week ago that he be indicted for bribery and fraud.
He has denied wrongdoing in what are now four separate investigations, including two in which he is personally a suspect. He says the allegations are a political "witch hunt".
In the latest case, police said former Netanyahu spokesman Nir Hefetz had offered through an intermediary in 2015 to help a judge win the post of attorney-general if she agreed to use the position to block any proceedings against Netanyahu's wife Sara.
Last September Attorney-General Avichai Mandelblit said he was considering indicting Sara Netanyahu for fraud over suspected use of state funds for personal dining and catering services amounting to some $100,000. She has denied the allegations and a final decision on charges is pending.
A spokesman for the prime minister and his family said no such attempt to bribe the judge had taken place.
"Nir Hefetz never proposed this hallucinatory offer to the prime minister and his wife. He was never asked to make such a proposal, and we do not believe Hefetz would even imagine doing such a thing of his own accord," the spokesman said.
A lawyer for Hefetz could not be reached.
In the other case revealed on Tuesday, police said they had arrested Hefetz and another Netanyahu confidant, Shlomo Filber, who once ran the Communications Ministry, over allegations of corruption involving the telecoms firm Bezeq.
Bezeq's main shareholder, Shaul Elovitch, was also arrested, along with his wife and son, and Bezeq's CEO Stella Handler. Elovitch is a family friend of the Netanyahus. The arrests took place on Sunday but were not disclosed for two days under standard Israeli procedure.
Police suspect Bezeq received regulatory benefits in return for providing favourable media coverage of Netanyahu on Walla, a news website that is controlled by Elovitch's holding company Eurocom.
Elovitch has denied any wrongdoing, as have his wife and son, and Bezeq CEO Handler, a Eurocom spokeswoman said. Filber's lawyer declined to comment.
Netanyahu is not a suspect in that case but Israeli media said he was likely to be questioned soon.
Last week, police recommended Netanyahu be indicted in two cases. In one he is suspected of bribery over his acknowledged receipt of gifts from wealthy businessmen, which police say were worth nearly $300,000. In the other, he is alleged to have offered the publisher of Israel's biggest daily to curtail circulation of a rival newspaper in return for positive coverage.
Netanyahu, who has maintained his normal working schedule and is due to meet U.S. President Donald Trump in Washington on March 5, has denied all the allegations and vowed to remain in office to serve out his term which runs until 2019.
Mandelblit is weighing indictments in those investigations, with a decision possibly months away. (Additional reporting by Steven Scheer and Ori Lewis; Editing by Peter Graff)