The dead guy was in "a jealous rage."
Police said the homeowner was getting ready for work when he heard a knock on the door.The guy with the hammer was pronounced dead at the scene, from a gunshot wound to the chest.
The man told police Mahaffey hit him in the head with a hammer so he got a weapon to defend himself.
The man, whom police would not identify, was injured and was taken to a hospital for treatment.
Self-defense is a human right.