You go with that theory...
Just like a lot of the people populating our maximum security prisons.
ROFL!!!!!!!!!!!!!!!!!!!!
No kidding, what is the crime here?
Let me pose another scenario: The guy tries to rob you and is unsuccessful because you fought with him and knocked him out. Would you just walk away, or call the cops? Has a crime been committed? And if so, by whom?
Think about this. Are you SURE you want to call the cops? What if he isn't just "knocked out"? What if you caused a brain bleed and he died? But you didn't know it. Now you have a dead body there, and absolutely NO PROOF the guy tried to rob you. As far as the police are concerned, you had it in for this guy and just beat him to death. Are you still SURE you want to call the cops?