The rich kid with a brilliant school record was a ticking time bomb even before he turned up as an international student living in his father’s mansion block apartment in Britain. Classmates remember Umar Farouk Abdulmutallab as such a pious youth that he was nicknamed “Imam” and “the Pope” after rebuking them for failing to live up to religious principles. Suicide bombers typically take half a dozen years to descend from religious fanaticism to “martyrdom”, which appears to be the case for this young Nigerian, a security expert said. Acting alone as a “clean skin” rather than by mingling with...