Blood has always been an inevitable and crucial physical evidence. It made forensic science a revolutionary field of study. Furthermore it is omnipresent in all violent crimes. Blood is a vector which indicates the sequence of events in a crime and match the suspect to the crime scene. The DNA typing has got a significant impact on violent criminal investigations. What is blood? It is a body fluid in humans and other animals. It is composed of blood cells suspended in blood plasma which constitutes 55% of blood fluid, mostly water (92% by volume), it delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells. and contains dissipated proteins, glucose, mineral ions, hormones, carbon dioxide (plasma being the main medium for excretory product transportation), and blood cel...