If you kill someone, then someone else will kill you. No one is innocent. We all are guilty of something. But life and death is not about reincarnation. It is a growing experience.
Reincarnation is just a path of life.
It is there as a fact of life, a way of life. It is the same as breathing. You breath in life, you breath out death. Day is like life, and night is like death. The two make one.