The problem with this whole affair is that the evidence as presented has nobody committing a crime - but we have a dead body. Both participants seem to have made dumb decisions, both participants could claim fear of the other and thus lay claim to self-defense.
I used to think it was terrible that life was unfair. Then I thought what if life were fair and all of the terrible things that happen came because we really deserved them? Now I take comfort in the general unfairness and hostility of the universe.