Legal Question in Criminal Law in Ohio

Technically, if he is running away, the imminent threat of serious bodily harm or injury has been removed so shooting him in the back could get you charged with involuntary manslaughter at the least.

Alternatively, under the castle doctrine, if an intruder is in your home, you may be justified in a shooting which may result in the preportraitors death.

If the suspect is fleeing, do not shoot him in the back. Let him run.

Mr. Hess's answer is correct. The only thing that I would add is that one can never be sure when a person is truly fleeing or is simply retreating to get a better angle of attack on you. But that is not an argument that you want to have to make. Usually it is best to let him run.