Is it realistic to say we could have spotted the Christchurch mosque shooter, before he went on his evil rampage?

Or are we making judgements and a bunch of apologies now with the benefit of hindsight, and the collation of a large amount of information at a lot of expense from a lot of different sources.

For example, the Royal Commission on the mosque attacks found out that he'd picked the date six weeks in advance and even sent himself a to-do list of preparations.

It's dug into his childhood, and uncovered the long, slow burn Tarrant was on.

The family home scarred by domestic violence.

Being bullied unable to form relationships becoming a loner starting to show racist tendencies when he was a teenager.

Then he joins an anonymous online bulletin board...which has been linked to everything from child pornography to animal abuse to killing sprees.

He was active on a far-right Australian Facebook page.

He made donations, big ones, to extremist parties in Germany and gave funds to a neo-Nazi publisher in the States.

So what we see now with the benefit of hindsight is someone with a mind that over time got so twisted, so distorted, so bitter and angry and resentful, he was capable of conceiving his crime.

And when you have all the pieces together in a carefully compiled document, it's easy to say...Oh My God...how did we miss that?

But in the real world...I'm not so sure...when you consider he had no criminal record prior to March 15th.

What I'm saying is that hindsight can be 20/20.