The son of a Hamas founder was a long-term spy for Israeli intelligence and the "most valuable source in the militant organization's leadership" to Israel, according to CNN reports Wednesday.

Sheikh Hassan Yousef (C), a senior Hamas leader in the West Bank currently imprisoned in Israel, is surrounded by Israeli border police officers during a hearing in the Ofer military court near the West Bank city of Ramallah January 22, 2006.[Xinhua/Reuters File Photo]

Mosab Hassan Yousef, 32, is the younger son of Sheikh Hassan Yousef, a Hamas official who is serving a six-year term in an Israeli prison. Now he lives in California of the U.S.

It is claimed that Mosab worked for Israel's domestic security service Shin Bet since 1997 and was entitled a nick name "The Green Prince," which was refered to his relation to his father and the color of the Hamas's flag, which was quoted as saying by Associated Press.

Mosab was once jailed by Israel in 1996 and released in 1997. He was recruited during detention period.

The Israeli Haaretz daily reported Wednesday that Mosab Yousef prevented dozens of Hamas attacks against Israelis, including suicide bombings, saving hundreds of lives. The paper said he also helped put several senior Palestinian officials into prison.

Hamas, which still suspects that Hamas informants helped Israel assassinate a top Hamas operative in Dubai, thought the claims to Mosad Yousef as a lie and said they were part of an Israeli attempt to weaken the movement.

Mosab's father announced that Hamas knew of his son's contact with Israeli intelligence and adding that he "was not on any day an active member in the ranks of Hamas, in the wings of the movement."