problem:

I saw a movie called "Red Belt" several years ago. This film focuses on one martial arts instructor's goal to be true to himself and his students. His teachings were designed to protect the people and not spectacularize (is that a word) the art. In a bind for money, he agrees to fight in a Mixed Martial Arts competition. I don't want to ruin the movie,

Required:

Question: If he is attacked on camera and defends himself with a single punch that, at first "knocks out", but in reality kills his attacker, what do you do?

Question: How would you work the crime scene, explain your hypothesis as to what happened and how you would test your hypothesis and what kind of testing do you think would be useful?

Could someone explain this to me?