Narration of a Perfect Crime

A perfect crime is one in which it is impossible to point out a culprit to punish him which is A VENGEANCE TAKEN BY SOCIETY forbidding the victim's relatives to do it by their own hand on pain of also penalizing them. And what does it mean to point out a culprit? For this it is necessary to establish the existence of a victim a weapon a motive and an executor of the crime that is the person responsible. And is this always possible? Many times the above requirements may not be met and a crime may go unpunished at least for a while but by Universal Conspiracy the criminal always leaves loose ends that one day will allow to discover him.