A comparative study on variations in bloodstain patterns due to change in surface angles-using blood from four common animal species

Abstract

In crime scene investigations, particularly in cases of homicide, the pattern or the shape of bloodstains at the crime scene is of crucial importance. Bloodstain pattern defines the facts surrounding some incident that is in question. The shape and size of the bloodstain pattern is helpful in determining the area of convergence, point of origin, the direction of the blood droplet at the time of impact, the angle of impact, the nature of force involved, direction from which force was applied, the nature of the object used and the relative positions of the suspect, victim and other related objects during the incident. When the examination of bloodstains is done efficiently and carefully and if all possibilities are exhausted, shape, location and site of bloodstain can give important details about the circumstances of the crime. Keeping the importance of physical properties of blood in mind the present study is carried out with the aim to study the inter species variations in the patterns formed by the blood of four commonly found animal species; pig (Sus scrofa domestica), goat (Capra ibex), human (Homo sapien sapiens) and chicken (Gallus gallus), and red ink as control. In the present study, the variations in bloodstain pattern of four common animal species, when blood is allowed to fall from a fixed height at various surface angles are demonstrated.