have there been any suicide bombings in Aus? or Canada? even in Israel of recent times?
there are other options that police might investigate, such as Victoria's neonazi mob, who may have shot the school.
certainly the culprits may have been Muslim extremists but it still takes a psychopath to shoot up a school.
I'm just saying there's no need to jump to hasty conclusions based on preconceived notions of blame. such haste often leads to mistaken identifications.