(JNS) Israeli police and the Israel Security Agency (Shin Bet) on Saturday night arrested a 26-year-old resident of Kfar Saba in connection with a death threat against Israeli Prime Minister Benjamin Netanyahu.

The arrest followed a report regarding a threatening letter placed on the grave of the late Yoni Netanyahu—the prime minister’s brother who was killed in the 1976 Entebbe raid—at the Mount Herzl National Military Cemetery in Jerusalem. Upon receipt of the report, a joint investigation was opened by the Israel Police and Shin Bet.

During interrogation, the suspect admitted to placing the letter at Yoni Netanyahu’s grave. The suspect is set to appear at the Rishon Lezion Magistrate’s Court on Sunday for an extension of his remand.

The letter, which was written in both Hebrew and English, stated, “This is a threat of the first level,” and indicated that Netanyahu would not reach the age of 74.

Netanyahu and his brother Ido last week participated in a memorial ceremony at Mount Herzl on the 47th anniversary of Yoni’s death.

Israeli media also reported on Sunday that on Friday, a 47-year-old resident of Kiryat Gat was arrested after calling the police station in the city and threatening to kill Netanyahu.

“The Shin Bet and the Israel Police will deal with severity and with all the means at their disposal in the face of a threat of harm to public figures and will prosecute those involved,” a joint statement said.