Again, back when I was that age, boys caught in that situation DID NOT stay to argue...they ran for their lives out of fear of the girl's father.
Girl - totally wrong for inviting him in and lying
Boy - totally wrong for being there and staying to fight
Dad - wrong for taking a life (could have shot to wound, not to kill) and not realizing that his daughter would be screaming if she truly did not know him and he was in her bedroom 4951