If you shot the perp in your house or on your porch while he was facing you - self defense would apply.
If you shoot him 35 feet from your door while he was running away, and he was unarmed, even after he assaulted you - you would be charged with murder or manslaughter.
Why would you suggest that he was running away? Is this what the media told you was one of the ‘facts’ of the case?