Mis-Application of the Make My Day Law Justifies Murder

Are states like Oklahoma and South Carolina using the Make My Day Law and Castle Doctrine law to justify murder. When a person is killed allegedly breaking into a home or business is the homeowner or business owner's version of what happened suppose to be taken as fact, and never investigated. Is it likely that every case of alleged robbery was really a robbery? Should the law more clearly define what is perceived threat or imminent danger in regard to when the homeowner or business owner can by law kill another human being?