Why do I write Crime Novels?

I have always enjoyed reading crime novels, so why not write within the genre? It is a challenging genre that requires the writer to have a wide range of understanding character development, complications and pacing.
Someone commits a crime. Now three forces are engaged; the killer, the law, and in most cases the family of the victim, but rarely the family of the killer. These opposing forces will create a meandering river that twists and turns, as complication after complication occurs. Lives are washed ashore, but still the river or storyline continues to rush towards the falls that will shatter every life, from those who survive by holding onto the rocks and those who are lost, carried away by the pounding falls. The falls will shatter lives, hope, and ultimately understanding.
Generally the guilty party is held to account for their crimes. However the irony of crime novels is that although the killer is unmasked and his motivation is explained we rarely come to understand how they developed the motivation, how they came to accept the killing of another human being, what their childhood was like, what events in their years of development mentally allowed them to say, yes I will kill this person. This is the mystery we never learn, but one that I feel I need to explore.