There are however, certain general principles, three (3) in all governing the nature of things as far as the question of causation in homicide cases is concerned. It is to be pointed out in this connection that it is not every act of intervention or omission of a casual nature that will relieve the accused of liability for the subsequent death of the deceased. These principles, on which the accused might still be held to have caused the death of the deceased despite some form of intervention, are as follows: The first of these is where the earlier injury inflicted by the accused is held to be “an operating cause” and a “substantial cause.” See the cases of R. v. SMITH (1959) 2 ALL ER 193; QUEEN v. EGUABOR (No. 2) (1962) 1 ALL NLR 541. It is to be stated here that the intervening act may not obliterate an earlier injury inflicted by another person, where the earlier injury inflicted is adjudged not mortal, but may cause death in combination of the subsequent injury inflicted by the accused. In that kind of situation, the accused and that other person are both guilty of homicide. A second set of intervention is where the death of the deceased is due to some act done by the accused, which act is an actual consequence of the accused persons act. The accused will of course be liable if it is shown that his act is foreseeable as likely to occur in the normal courses of events. Here the injury inflicted by the accused is not regarded as “operating cause,” but the accused will be liable to have caused the death of the deceased. It must, however be shown that the act or event was the natural consequence of the accused persons act. See the cases of MICHAEL v. STATE (2008) 9 MJSC 61 AT 73; ALHAJI MUAZU ALI v. THE STATE (2015) LPELR-24711 (SC) and UMMARU v. GWANDU N. A. (1961) 1 ALL NLR 545. The third set of intervention is anchored on the rule that ordains that the accused must take his victim the way he finds him. If a man is suffering from a disease, which in all likelihood would terminate his life in a short time, and another gives him an injury or hurt which hastens his death, this killing constitutes murder simpliciter. See the cases of R. v. HAYWARD (1908) 21 COX C.C.692; See also R. v. MURTON (1862) 3 F and F. 492. It generally does not lie in the mouth of the accused person to say that he did not know that his victim was suffering from a disease of such a debilitating nature, which in all likelihood would terminate his life in a short time, before the accused gave him the injury, which hastened his death. The pertinent question usually raised for the Courts decision in matters of this nature, is; what caused the victim’s death? If the answer is either a stab wound or a blow to the head, that is all there is to decide and no more.
— F.O. Oho, JCA. Nasiru v State (2016) – CA/S/78C/2015