Did the London bombers know?

The other day, Thomas Friedman wrote that the key to stopping jihadism is understanding why the London bombers took their fatal step towards destruction:

The secret of this story is in that conversion -- and so is the crisis in Islam. The people and ideas that brought about that sudden conversion of Hasib Hussain and his pals -- if not stopped by other Muslims -- will end up converting every Muslim into a suspect and one of the world's great religions into a cult of death.

But John O’Sullivan makes an intriguing argument that the London bombers may have been unknowing participants:

Here is the evidence: They bought return railway tickets. Their bombs were not strapped to their bodies but carried in knapsacks as if to be left behind on the trains. None of them was heard to shout the customary ''Allah Akhbar'' before the bombs exploded. Unusually for suicide bombers, they left identification on their bodies. And surveillance videotapes show them laughing and joking casually -- rather than grimly determined or prayerful -- as they caught the Underground train.

These little pieces of circumstantial evidence suggest the possibility the bombers were duped. Maybe they were told by their controllers that the bombs were timed to go off five minutes after being detonated rather than immediately. It would not be the first time that al-Qaida had deceived its devotees: Osama bin Laden revealed that not all the 9/11 hijackers were aware that the planes were to be flown into buildings. And the bombers' ''suicide'' would protect the terrorist network against the chance that they might be caught and persuaded to talk.

And this may be insignificant, but one of them had on a brand-new pair of sneakers. Hmmm. Duped, but not innocent, by any means.