Amir Ahmad Nasr was born in 1986 in Sudan, but when he was still a little child his father's career brought the family to Qatar and Kuala Lumpur, Malaysia, and young Mr. Nasr began his education at Islamic schools in those places. Memorization of the Quran was the core curriculum. His teachers taught him that Jews drink the blood of children and conspire against Islam. On Fridays he said "amen" to prayers calling for the destruction of the Jews. He dreamed of heroism: "I wished I could die and martyr myself for Islam and occupied Palestine."

He...