Yes, I am a Christian. I am of the researched conclusion that the originally translated commandment was "Thou Shalt Not Murder." This is a case of a human defending the life of another, as tragic as the consequences may have been. I am not judging any of these people regarding their place in heaven (or wherever they may end up).
You ask me (and people who agree with me, I presume) to confirm that "Killing is a crime." I'll say that murder and manslaughter are crimes. Self defense and, in some cases, acting to defend the life of an innocent persoon, are permissible under the law. Mr. Due Moore acted within the law in this case. I don't really think he used a "ranking" system but probably happened upon a man armed with a knife repeatedly stabbing an unarmed woman, who, most likely, did not want to be stabbed/murdered by the man with the knife. Who in the hell was he to rank his life over hers?
~U2Alabama