Serologists deal with the entirely blood-connected part. For crime scene investigators, blood spatter analysis has provided a powerful tool.
Recently blood spatter analysis had been done on the computers. Still, without the help of experienced professionals, it had not been possible to deal with such a sensitive subject. Bloodshed during crime or violence always leaves a pattern of its own, that never fails to tell the gory story of violence that took place. Mostly blood spatter analysis is a kind of elimination; reducing the possible number of suspects from a murder scene and narrowing them to a manageable limit.
There are a few unalterable rules about the bloodstain analysis. The smaller the blood spatters, it is considered, as greater energy was employed to create them and vice versa. Blood placidly planning would create a bigger stain, or calmer stains and when unlimited violence and force is employed, those blood stains create much smaller, but many stains.
If the analysis is done according to the guidelines, it provides a tremendous amount of information for any forensic evidence. Usually the analysis is based on the main characteristics of liquid blood: gravity, viscosity and surface tension. It is also conducive with the laws of mathematics and physics as literally every drop of blood tells a story, by showing the flow and possible cause of it. This means that the analysis mainly depends on the terminal velocity of falling blood drops, their size and shape. There is another very important factor: the characteristics of the target surface. The object on which the bloodstains are traced could become an important part of the enquiry. We all know that undying controversies still arise from the blood spatter analysis done after the unfortunate assassination of President Kennedy on that fateful day in 1963 and they simply refuse to go even after decades.
"Blood is perhaps the most valuable evidence in the world of forensic science because its presence always links the suspect and victim to one another and the crime scene It can provide information such as who struck whom first, in what manner, and how many times. Scrupulous analysis can destroy alibi and self-defence arguments for a crime" http://www.bergen.org/EST/Year5/blood.htm
Angled impact of the blood drops, depending either on the position of the victim, or on the aslant position of the target surface, too is of prominence. A horizontal target surface in motion would provide an entirely different kind of exhibit. High velocity blood spatters, low velocity blood spatters, dripped blood, dried blood, drying blood, splashed blood, fine mist of blood spray, arterial spurting, wiping patters, dragging patters, rolling patterns, patterns of transfer to another alien surface, flowing patterns all have a certain information for the analyst and with this information,