I disagree. Far from being psychologically normal, suicide terrorists are suicidal. They kill themselves to escape crises or unbearable pain. Until we recognise this, attempts to stop the attacks are doomed to fail.

When I began studying suicide terrorists, I had no agenda, just curiosity. My hunch was that the official version was true, but I kept an open mind.

Then I began watching martyrdom videos and reading case studies, letters and diary entries. What I discovered was a litany of fear, failure, guilt, shame and rage. In my book The Myth of Martyrdom, I present evidence that far from being normal, these self-destructive killers have often suffered from serious mental trauma and always demonstrate at least a few behaviours on the continuum of suicidality, such as suicide ideation, a suicide plan or previous suicide attempts.

Why did so many scholars come to the wrong conclusions? One key reason is that they believe what the bombers, their relatives and friends, and their terrorist recruiters say, especially when their accounts are consistent.