If a criminal kills someone, how would we explain our action in putting him/her in jail, or executing him/her, while we believe it is done by oneness?
In order to understand these seemingly complex questions we have to reach some heart-felt knowing of Oneness. Oneness is too vast for the individual mind to comprehend, however we'll get a glimpse when we start looking deeper into the unreality of time and space.
We have a linear brain in order to survive and so we see things from the perspective of change, motion, events and thus time. Time is relative to motion as Einstein has proven through his theory of relativity. This means that although we experience linear time yet in Reality there is only holographic essence. Oneness also means that everything is One and absolutely nothing is separate or could ever be. In this Oneness we are all perfect and live in our True Home (unconditional love, peace, joy, etc). This raises another question -- are there two realities then, linear and holographic? The best explanation is given in 'A Course in Miracles' when it says that our life script has already been written. This means that everything that seems to happen has already happened. The life script that contains murder, suffering, pain, limitation etc is the illusive and delusive linear time. Einstein said that past, present and future occur simultaneously and that, in itself, boggles our linear individual mind. Again, this is something that is recognized when spiritual awakening happens where nothing is born and nothing dies because there never was anything but Oneness (our true Home).
It seems that we all have two life scripts already done -- ego script containing karmic consequences of acts and thoughts done in the past and are repeated due to unresolved issues like unconscious guilt, fear of the unknown, etc. We also have a Holographic script where we are living in unconditional love and eternal peace and joy. When we start to forgive (see clearly the illusion of) then our ego script begins to shift into our holographic true essence where nothing has actually happened but only seemed to happen.
Another way of looking at this is two-fold - either through our egoic interpretation or Oneness interpretation. If something drastic seems to happen to us then we can forgive it by seeing that worry, complaining, hatred, anger, revenge will not only NOT WORK but exacerbate the situation because our interpretation says, "This is awful and I must control it!" If, on the other hand, we see that what happens to us is due to unresolved feelings of what we might have done to others or to ourselves through our belief system, then we can forgive it (give it forth to Oneness) and thus avoid the karmic consequences of such action. When we forgive (give forth to Oneness) then whatever was written in our life-script as 'painful' will be transcended through the collapse of time and space in our favor. I know that this is hard to believe but this is fact and I know it beyond any doubt. This is why waking up to our true nature can be so freeing because we will see that we are guiltless, free, innocent and whole. The only rule and law in life is LOVE and anything that you do with love, whether it is sex, affection, giving, dancing, celebrating or enjoying is the freedom of our true nature. While the ego script is filled with rules, man-made laws, conditions and fears; our True Oneness Holographic script is freedom, innocence, guiltlessness and unconditional love. In this holographic sense there is no 'wrong' in anything because it is all acted through Oneness known as love. When in our daily life we hang or kill a murderer by law we are still perpetuating the same karmic principles that will remain unresolved in our psyche to be re-experienced in our life and to learn forgiveness. The reason there are criminals, murderers, corrupt politicians, selfish lawyers and vengeful police is because they are carrying out unresolved unconscious guilt. This cycle will keep repeaing lifetime after lifetime until we learn that we are Oneness and thus spiritual perfect unconditional love. We may experience many thousands of lives until we discover there were no lives but Oneness doing everything and bringing us Home.