This is more of a psycho movie.
It's more about the cop who got fixated in a case because of a promise he made to the mother of the victim.
This movie is a good eye opener for policemen, soldiers = men and women in uniform, the organization must not anymore give assignments to retiree employees 6 months prior to retirement no matter how good they are so they can have a good transition in their life changing style, routine.
They must start a psychological session / therapy program (at least for 6 months) for retiree policemen and soldiers so they can cope with their new life. And that they will remain productive and whole as a person and as a citizen of the land.