Uri Yisrael served as a fighter in Caesarea, the Mossad Special Operations Division, and has a unique record: He lived under an assumed identity for the longest time period – 15 years.

Yisrael and another fighter dubbed "Isaac" (his name is still under censorship) were part of the Ulysses Project – a secret Israeli intelligence project in the 1950s and 1960s.

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They were planted as Arabs, married Palestinians , had children and were incorporated into the Palestinian community as businessmen. They were the first to provide intelligence regarding the establishment of Fatah , and took part in the first plans to kill Yasser Arafat and Abu Jihad.

Uri Yisrael's son is 50-years-old today and lives abroad. To this day, he does not know that his father is not a nationalistic Palestinian but an Israeli Mossad agent. He also does not know he has a half-brother: Shai Yisrael, a lawyer, Uri's son from a Jewish woman.

The story begins in 1950, when Isser Harel, then the director of the Mossad, set up a unit called Ulysses, with the purpose of planting agents within the Palestinian refugee community in the West Bank and in the neighboring countries. The recruits were Jewish Zionists, recent immigrants from Arab countries. They joined the secret unit after Harel and his men convinced them it was a "top priority national mission."

It was a brutal mission. Once recruited, some of them before the age of 20, they were completely cut off from their families and sent to live in hidden apartments in Jaffa for a training period of a year and a half. During this time, they practiced their cover stories and studied Islam, espionage and sabotage.

"These were difficult times," said unit director Sami Moria, "when I used to take their mail to their families, one of the mothers would always beg, 'let me see him, even for two minutes, even on the street, even from afar, I just want to know my boy is ok.' And there were tears. Lots of tears. But I couldn't agree, it would disturb their process of formulating a new identity."

Only nine completed the training course and were planted within the Arab-Israeli community. Their purpose was to warn against rebellion, be there should the areas be conquered by the enemy – and go out to the Palestinian communities around the world and Arab countries.

The process was difficult and arduous and great efforts were made in order to provide reliability. Two of the recruits, for example, were dressed in rags and posed as Palestinian refugees who crossed the border from Jordan to Umm al-Fahm. They went into an Arab inn and ordered coffee. Moriya and the Shin Bet crew, watching them from a distance, knew that the inn was filled with Israeli police informers. And indeed – within a half hour, eight police cars surrounded the area. The policemen dragged the two "infiltrators" outside, and beat them vigorously with their fists and clubs.

Most of the Ulysses men returned home in 1959, but two of them were transferred to the Mossad and continued living as Arabs. With their operators' encouragement, they got married, had children and pretended – even to their families – they were nationalistic Palestinians who were filled with hatred towards Israelis and Jews.

In the first half of 1964, the two agents reported the formation of a new Palestinian group. It was headed by two men whose names meant very little then to the Israeli intelligence – Khalil al-Wazir, "Abu Jihad", and Yasser Arafat, "Abu Amar".

Uri Yisrael, under the alias Abed al-Hader, even provided the apartment in which the Fatah heads met in order to plan how they would wipe Israel off the map and establish Palestine in its place. The men of Colossus, the Mossad surveillance unit, heard everything through microphones planted in the apartment's walls.

In June 1964, Rafi Eitan, then the head of Mossad in Europe, turned to the director of the organization, and asked him to order Caesarea to break into the apartment and kill everyone in it. In a letter sent to Meir Amit, then Mossad director, Eitan wrote: "We have an irretrievable access to the target. It could be easily done. We should kill this kettle while it's still small."

Meanwhile, a dramatic scene occurred at the house of Uri and his wife in Beirut. He was in the middle of a Morse broadcast to Israel, when his wife surprised him and entered the room. Yisrael, who has come out of much more dangerous situations before, suddenly decided to tell his wife the truth: I'm not a Fatah-supporting nationalist Palestinian, but a Jew. And a spy for the Mossad.

Read the full story in Friday's Yedioth Ahronoth '7 Days' magazine

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