That question is probably best answered with a visit to the state prison inmates. They would have first hand knowledge.
There could be someone on here who has lawfully killed someone. I'd like to know as well. Say someone was breaking into their home and they shot and killed them, do you feel bad, do you wish you would have talked to them first, did you eat their heart to gain their strength?
No, but one time I killed the dog... <iframe title="YouTube video player" width="480" height="390" src="http://www.youtube.com/embed/ytj0HxhaHVA" frameborder="0" allowfullscreen></iframe>
I'll say that my nephew who was a Marine in Iraq hated this question and thought anyone that asked it was incredibly insensitive. He said his feeling and that of most marines was that if they did end up having to kill someone, the last thing they wanted to do was talk about it. But he said every time he would be out and someone found out he served in Iraq someone or more than one person would always ask that question.
Fixed it for you, FB. And yes, vets typically don't talk about this subject. At least those I know and have known do not, and that includes my late father during WWII (waited until I was 30 to tell me about a very bloody action he was in, and only did so because he didn't think he had long to live and thought I should know), my uncle, who was a Marine officer at Chosen in Korea and was neck deep in action (and has never talked about it to anyone, except my late aunt), and friends who were in Vietnam.
Thanks I went back and edited it after seeing your marvelous proof reading job. Yeah my father in WWII didn't like talking about it, nor did my grandfather who was in WWI. He talked about it even less, and he was in more heavy combat situations.
My cousin woke up to someone in his house going through cabinets and shot and killed him. Turned out the guy did have a gun, but he still felt pretty bad about it.