The Magistrate's Court in Netanya convicted Hagai Amir on Sunday of threatening the life of the prime minister.
Hagai Amir is the brother of the Yigal Amir - the assassin of former prime minister Yitzhak Rabin. He asked prison guards, "What, are you afraid that I'll kill Sharon? I could pick up the phone and take care of him."
The judge determined that the guards' version of the story was accurate.
Amir is currently serving a 16-year sentence for his involvement in the murder of Rabin.