Mosab Hassan Yousef says he will be killed if he is deported from the United States to the West Bank. The oldest son of one of Hamas' founders, he was an Israeli spy for a decade, and he abandoned Islam for Christianity, further marking him a traitor.

He is scheduled to plead his case Wednesday to an immigration judge in San Diego, four months after publishing memoirs that say he was one of the Shin Bet security agency's best assets and was dubbed The Green Prince, a reference to his Hamas pedigree and the Islamists' signature green color.

Yousef's case seems straightforward: Helping Israel find and kill members of the militant group would make him a marked man back home. Nearly two dozen members of Congress wrote Homeland Secretary Janet Napolitano this week that Yousef would be in "grave danger" in the Middle East. Former CIA Director James Woolsey says his deportation would discourage other potential spies.

"It is not an exaggeration to say that such an action would set us back years in the war on terrorism," Woolsey wrote in a letter released by Yousef's attorney. "Mosab's deportation would be such an inhumane act it would constitute a blight on American history."

But the Department of Homeland Security isn't convinced and wants him gone, calling him "a danger to the security of the United States" who has "engaged in terrorist activity."

Yousef, 32, settled in Southern California after stepping off a plane in Los Angeles with a tourist visa in January 2007. He remains free while his application for asylum is considered.

"Exposing terrorist secrets and warning the world in my first book cost me everything. I am a traitor to my people, disowned by my family, a man without a country. And now the country I came to for sanctuary is turning its back," he wrote on his blog last month.

Asylum applicants can close their hearings to the public, but Yousef welcomes the publicity. He urges supporters to contact the Homeland Security attorney assigned to his case and invites anyone in the San Diego area to attend the hearing.

U.S. Immigration and Customs Enforcement, the agency within Homeland Security that is arguing the government's case, declined to comment, saying in a statement that it "respects the privacy of all individuals involved in the immigration litigation process."

Homeland Security called Yousef a terrorist danger when it denied asylum in February 2009 and, in court documents provided to The Associated Press by Yousef's attorney, says he "discusses his extensive involvement with Hamas in great detail" in his recent memoir. It cites a passage in which Yousef identifies five suspects in a 2001 suicide bombing to a Shin Bet official and admits that he drove them to safe houses. It was not more specific in its pre-hearing briefing about the threat he may pose to the U.S.

Yousef says his intelligence work for Israel required him to do anything he could to learn about Hamas and that neither he nor Israel knew they were suspects in the suicide bombing when he gave them rides.

"Yes, while working for Israeli intelligence, I posed as a terrorist," he wrote. "Yes, I carried a gun. Yes, I was in terrorist meetings with Yassir Arafat, my father and other Hamas leaders. It was part of my job."

Israel has not commented on Yousef's claims, though members of the Knesset Foreign Affairs and Defense Committee wrote him this month to thank him and recognize his work for Shin Bet.

His attorney, Steven Seick, said Shin Bet will not have a representative address the immigration judge but that the now-retired officer who recruited and supervised him, Gonen Ben-Itzhak, is expected to testify.

Ben-Itzhak wrote that hundreds of Israelis and Palestinians owe their lives to Yousef for preventing violence. The officer is identified only by a pseudonym, Loai, in court documents.

The government does not plan to call witnesses, Seick said.

Yousef's attorney wanted an FBI agent to support Yousef's claim that he gave information about Hamas and terrorism. The FBI refused but said it would not object if Yousef testifies he met twice with agency personnel.

The U.S. government considers Hamas a terrorist organization. Hamas says it provides schools and other social benefits to residents in the areas it controls.

In his book, Yousef describes growing up admiring Hamas and hating Israel, leading him to buy a couple machine guns and a handgun in 1996. He said the guns didn't work and that he was arrested by Israeli forces before he killed anyone.

Yousef says he started working with Shin Bet after witnessing Hamas brutalities in prison that left him disillusioned. He gravitated toward Christianity after his release in 1997, joining a Christian study group after a chance encounter with a British tourist at the Damascus Gate in Jerusalem.

Yousef says he joined his father, Sheik Hassan Yousef, at many meetings with Palestinian leaders and reported them to Shin Bet. His father, a senior Hamas leader who is serving a six-year sentence in an Israeli prison, disowned him in March.

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Online: www.sonofhamas.com

(This version CORRECTS Yousef's age to 32, sted 34.)