It is an important question but it is not the only one.There is a strong and undeniable link between social deprivation and crime...
Exactly. So the question is what set them on that road and how do we minimise future traffic flows down it.
We have whole generations on the road already here and elsewhere.
That is a police\justice system problem. It's not going to be rectified by long term improvements in society or education, although as you have noted on other threads addiction support etc is very poor here. In the short to medium term those kinds of improvements are more likely to deliver immediate results.
That said, the nature and timing of the crime in this case is highly unusual and may be beyond any of the above.