There is to my knowledge plenty of gaffers who's either server or is serving in your countries army. And while a great majority probably haven't done anything so traumatic as killing someone, it must have happened to someone - you are a soldier after all and you will shoot to kill if you have to.
But you don't have to be a soldier to have killed someone, these sort of things happen to be done by civilians as well from time to time. And assault, rape and torture aren't committed by soldiers alone, I suspect that civilians commit more of these atrocities.
I do realize that asking people here on this forum whether they've done these things is pretty pointless, I doubt many will step up and share with us something that might haunt them. But anonymity gives you a sense of security rarely found elsewhere, you can pretty much come out and say straight out the things you've done in your past without any real world repercussions (unless you're confessing to a crime you have yet to pay for, please don't do that).
So I suppose that you can in this thread tell us your experiences, whether you've ever been put in a position or willingly entered one where you've had to inflict any of the mentioned things on another human being. And how it has affected you and your life since you did whatever it was that you did.
And finally a word to DetectiveGAF: Please don't.