Professor Paul Mullen

They were almost all young men who felt that they had been ignored, humiliated, looked down upon.

So it was their way of saying, I am powerful, I'm not to be ignored, and then to be killed.

Now, in Malaya, at that time, to be put into a mental hospital was a shame of the whole family.

So far from being a glorious death, they had this humiliating outcome.

Was it effective?

Yes.

Extraordinarily effective.

It almost died out completely over a period of about 10 years.

Exactly right.

I mean, it wasn't confined, in fact, to Malaya, but it was most intense there.

There were other parts of so-called Far East, from the Europeans' point of view, where it occurred occasionally.

But there, it really was embedded into the culture.

There was a schoolteacher.

He had quite a lot of personal problems.

He killed his wife and children, and then he shot and killed several people, but a couple of them ran at him, disarmed him, and he went to trial, was found insane.

For Australians, it's the Port Arthur massacre which stands out.

In America, there's almost too many to mention, but I suppose the massacre at Columbine was probably the one that would immediately jump to mind.

As a result of two boys' teenage rage, 25 feared dead.

And, of course, in Britain, in Scotland, it would be the Dunblane massacre.

So it spread round the world.