These two things don't have a whole lot to do with each other.

Sure, crime isn't 'simple cause and effect'. But it is still as simple as 'means, motive, opportunity' and if means are plentiful that reduces the friction on the way to crime.

As for the bomb threats, I have no idea, but I also don't see them as the kind of crime that we are discussion here (violence, in particular). Bomb threats are a denial of service attack, actually killing or wounding people is on another level (at least, it is for me).

One suggestion: the widespread use of ANI + mobile phones and the disappearance of pay-phones + cameras on every street corner make it a lot harder to call in a bomb threat without getting caught.

"Means, motive, opportunity" is a helpful framework, but that doesn't make violence predictable. For example, there are many religions and ideologies that people can latch onto and which crazies get motivated by what ideology doesn't seem all that predictable? It could come from any political point of view or be based on something obscure.