Blood Spatter Analysis in Forensic Science - Essay Example

113648 The recent unprecedented interest in forensic science techniques has increased with media coverage of real scenes and cinema and TV coverageof fictional crime dramas. Accordingly, importance of blood spatter analysis along with the other branches of Forensic Science is in the public eye today. Blood spatter analysis, considered to be the most important part of forensic science dealing with crime scenes, is neither an isolated branch of it nor a remotely singular process. Instead of being a single work, this job is broken down into many sections, headed by trained professional specialists, dealt separately by the crime labs. 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. "Usually it is of much more importance to establish what mechanism could not have occurred to produce a bloodstain pattern," http://www.brazoria-county.com/sheriff/id/blood/ 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. "Bloodstains are a source of important forensic evidence regarding: Origin(s) of bloodstain. Distance of bloodstain from target. Direction from which blood impacted. Speed with which blood left its source. Position of victim & assailant. Movement of victim & assailant. Number of blows/shots". http://www.dundee.ac.uk/forensicmedicine/nurse/notes/Bloodspatter.htm 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, the percentage of better evidenced cases are going up. "interpretation of blood spatter patterns and other evidence at crime scenes may reveal critically important information such as the positions of the victim, assailant, and objects at the scene; the type of weapon that was used to cause the spatter; the number of blows, shots, stabs, etc. that occurred; and the movement and direction of the victim and assailant after bloodshed began," (Akin, L.L., Blood Spatter: Interpretation at Crime Scenes, The Forensic Examiner, Summer 2005 v14 i2 p6(5) He says it is like tracking and needs an extensive professional training. And it determines the events as to what must have occurred and this evidence, usually, barring a very few controversial instances, had always been one of the most dependable witnesses on the victim's side, leading the police to the murderer. There is another important factor contributing to the ultimate analysis. Sometimes things are judged because of a void that might have prevented the blood from reaching the ground. It could be anything, from the body part of the victim, or the attacker, or the object used for killing, or any other object that has been removed from the crime scene. So, this void is important in the analysis. Depending on the Locard's principle of exchange, whenever two objects meet they unfailingly impart certain matter of themselves to the other. If a person, attacker, intruder or a potential witness was present, the void without bloodstain is what the person had taken with him from the crime scene. This, combined with the conventional high velocity blood droplets and low velocity droplets that have their own characteristics and could be judged based on them, almost recreate a murder scene. Recently, in spite of high profile the analysis enjoys, there had been many sad controversies. Sion Jenkins was convicted for the murder of his stepchild Billie Jo-Jenkins and was sentenced to life in prison in a unanimous verdict. Judge spoke about the compelling evidence that had been provided by the blood spatter found all over Jenkin's clothes worn at the time. Jenkins, the Deputy Headmaster, who was supposed to have killed his stepdaughter in a fit of rage, vehemently denied having done so and had been continuously fighting for his freedom and reopening of the case. For the blood on his clothes, he gave the almost unbelievable reason as the result of a bubble burst in Billie's nose and he attended to her. This sounds genuinely farfetched and the Jury cannot be blamed for arriving at a guilty decision. The defence was of the opinion that the blood spatter pattern was consistent with the person who wore those clothes and delivered several blows on the victim's head. Other circumstantial evidences and his wife saying that he was always volatile and angry too had helped the Jury to arrive at this decision After nine years of serving a prison sentence that came to him mainly as a result of wrong blood splatter evidence, today, Jenkins is a free man after another trial has acquitted him. During these years, police and the defence had been unable to find any other definite evidence against Jenkins and the whole thing hinged on the blood spatter evidence. It is also told by the media that the real murderer escaped because of the single-minded determination of the police to convict Jenkins and being perpetually on the wrong trail. On 9th February 2006, he had been acquitted of the murder in a much-awaited retrial. The blood spatter verdict was not convincing enough any more. Now the laboratories have initiated kit based pat tern analysis that is considered to be highly dependable and quick. The objectives of the analysis in every case usually remain the same: 1. "Establishing the relationship between dropping height and blood drop diameter; 2. Recognising the patters around the drop, such as satellite spatter or spines; 3. Developing an understanding of types of bloodstain patterns; 4. Creating and examining vertical blood drop patterns on various textured surfaces; 5. Differentiating between high velocity and medium velocity impact spatter," (based on http://www.bergen.org/EST/Year5/EA/Serology2_1.htm According to Schiro G., analysis could be of three types: 1. Conventional Serological Analysis. 2. Restriction Fragment Length Polymorphism (RFLP) DNA analysis. 3. Polymerase Chain Reaction (PCR) DNA analysis. He also insists on documentation and evidence sharing, so that all the innocent suspects could be out of reckoning and the guilty could be punished. "The investigator should thoroughly document every aspect of the crime scene investigation from the initial walk through to the securing of the collected evidence. Documentation is necessary to record the condition of the crime scene and its related evidence as closely as possible to their original condition at the time of the crime," http://www.crime-scene-investigator.net/blood.html The new methods being employed by the forensic science today for the analysis have advanced beyond expectations. Controversies do come as a draw back, no doubt, but they are far and few. In the meantime, there is no doubt that the blood stain analysis has firmed its base and importance and no murder enquiry, leaving blood in the murder scene is complete without the help of blood spatter analysis. Now we have arrived at a conclusion that the analyst might make a mistake; but not the methods of this silent witness that rules the murder scene. This analysis, along with DNA testing have formed a formidable force against every murderer. BIBLIOGRAPHY: 1. (Akin, L.L., Blood Spatter: Interpretation at Crime Scenes, The Forensic Examiner, Summer 2005 v14 i2 p6 (5). ONLINE SOURCES: 1. http://www.brazoria-county.com/sheriff/id/blood/ accessed on 27.2.2006. 2. http://www.dundee.ac.uk/forensicmedicine/nurse/notes/Bloodspatter.htm accessed on 27.2.2006. 3. http://www.bergen.org/EST/Year5/EA/Serology2_1.htm accessed on 27.2.2006. 4. http://www.bergen.org/EST/Year5/blood.htm accessed on 27.2.2006. 5. http://www.crime-scene-investigator.net/blood.html accessed on 27.2.2006. 6. http://www.innocent.org.uk/cases/sionjenkins/ accessed on 28.2.2006. 7. http://news.bbc.co.uk/1/hi/uk/124813.stm accessed on 28.2.2006. 8. http://www.justiceforsionjenkins.org.uk / accessed on 28.2.2006. Read More