ILEX Criminal Scenario

Mary takes John out on a date.
While in a pub a guy called Evil starts coming on to Mary. She laughs it off and John stays quiet. Then, when he goes to the gents, John is attacked by Evil who uses a knuckle duster and punches him in his ribs - breaking one of them. Mary hears people shouting "fight, fight" and goes out to see John in a heap on the floor. She goes to Evil (assuming it was he who had hit John) and slaps him accross the face. The Police are called and Evil admits that he punched John, but also argues that he was attacked by Mary.
Break into Law Firms representing Evil and Mary - presenting criminal law arguments. Do not forget the need for arguments concerning both the actus reus and mens rea.