People that live their lives violently, live in a subjective world of violence. The "karma" of violence is not that if you shoot someone, then someone shoots you--though it often happens that way--it's that you live in the mental abode of violence. The abode of violence is a paranoid place, fearful, edgy, aggressive. There's no place to relax and feel at peace. If you ever watched the TV show The Sopranos, the show creators did this tremendously well--showing that no matter how much opulence and luxury Tony Soprano enjoyed, his life was hellish, he was always looking over his shoulder, always having to assert his power.
If you are a thief, whether by stealing in the grossest sense or in the corporate sense of taking more money and resources than you need at the expense of destroying the environment and hoodwinking honest people, you live in a thirsty, fast-paced, hungry world, where you're always obsessed with getting more. You might get to keep everything you steal and never get called to "justice," but you never get to fully enjoy it, because the very mind that accumulates material wealth is incapable of stopping and enjoying it.
And so on... I think this is very important because it gets at the heart of what the Buddha's teaching was all about. Which is that we look to the wrong place for answers and for happiness. We look to the world outside, not to the thinking that makes that world seem a certain way. We believe our thoughts and don't look to the thinker. As long as we keep looking outside ourselves, we stay stuck in the same repetitive cycle of dissatisfaction.