WRT Breivik, I’m not so convinced that he was unstoppable, though I fully accept the prospect of the complete lone-wolf. The reports of Breivik’s on-line persona, if accurate, seem to indicate that it was wide enough that automated analysis might have had a chance of identifying it as sufficiently disturbing to deserve a closer look by a human investigator. We can only look at his manifesto in retrospect, but if he had already been flagged as a person of concern, would its posting several hours before the attack have been enough time to raise an alert? Perhaps even to do something to stop his second attack if not his first?