With some fanfare in the weeks since the London bombings, the British authorities have quickly detained the main surviving suspects and, just as rapidly, embarked on a high-profile campaign to expel prominent, foreign-born Islamic figures as part of promised measures against extremism. But the investigation into the lethal July 7 attacks and the failed July 21 attacks seems to have undergone some less publicized changes that have left important questions unanswered, in public at least. Some leads, once hotly pursued, have fizzled out. Others have proved to be blind alleys.Full Story