Discuss, share and compare stain pattern analysis methods, protocols, and research for the enhancement of forensic bloodstain pattern analysis bpa techniques. How scientifically accurate is dexter morgans tv character blood. Bloodstain pattern analysis involves studying blood spatters on walls, floors and furniture, using the length and width of elliptical. Our experts are studying a variety of forms of pattern and digital evidence, to include bloodstain analysis, and are working to develop new tools to improve accuracy. Blood pattern center for statistics and applications in. Performing this directional analysis of impact patterns can provide the bloodstain pattern analyst with crucial information about the location and posture of an. Bloodstain pattern analysts help crime scene investigators reconstruct the events of a crime by interpreting the physical evidence of bloodstains national research council nrc, 2009. Particular attention is given to determining the angle of impact that caused a blood stain. A definitive documentary on blood spatter analysis has yet to be made but this forensic files case study is by far the best program on the subject to this date. About bloodstain pattern analysis the science of dexter. But his conviction for murdering her was based on junk sciencelike thousands of others.
Bloodstain pattern analysis bpa is the study and analysis of bloodstains at a known or. In fictional television shows such as dexter and csi, patterns in blood splatters at the scene of crime can be counted on to lead investigators. Impact spatter blood stain patterns created when a blood source receives a blow or force resulting in the random dispersion of smaller drops of blood. How blood spatter experts learn their trade in a room filled with horse blood. Dexter is a pretty cool shotwime series that started in 2006 and ended in 20. Bloodstain analysis convinced a jury she stabbed her. As part of a bloodstain pattern analysis bpa course being delivered at the ontario police college, students were instructed to create a doubleblow impact pattern. According to the book blood stain analysis by terry l. In the blood spatter training room even the signage is realistic. Alternatively, there are now computer programs that simply require the. Dexter morgan works as a bloodstain pattern analyst or blood spatter analyst, as he calls it for the miamidade metro police department. Developing a physicsbased algorithm to predict the region of origin of bloodstains by inspection of a blood spatter.
The stains form a kind of line or path usually made by the suspect after injuring or killing the victim or injuring themselves. To analyze a bloodstain pattern, an expert relies on three main interrelated elements. Collecting and organizing a database of highquality blood spatter videos and images. Dexter works as a blood stain pattern analysis at the miami metro police depatrment by day and doubles as a killer of killers by night. He takes one look at the bloodstained crime scene, and with all the expertise of a bloodthirstykillerturned blood spatter analyst, recounts the murder as if he had seen it happen. A five 5 ml pool of sheeps blood was placed on top of a wooden post and struck with a hammer, to create a classic vshaped pattern. Today, we analyze dexter and the job of bloodstain pattern analyst. Bloodstain pattern analysis uses biology, chemistry, physics, and mathematics especially trigonometry. Of course, analyzing blood spatter isnt as simple as fictional bloodstain pattern analysts like dexter morgan make it appear. Design and encourage the implementation by practitioners of a quality assurance program in bloodstain pattern analysis and to advise the forensic bloodstain pattern analysis.
In the show, dexter usually only needs to be at a crime scene if blood was found, and the reallife position is similar. How to become a blood spatter analyst criminal justice programs. Bloodstain pattern analysis is a forensic discipline in which, among others, the position of victims can be determined at crime scenes on which blood has been shed. Dexter and the officer are the only people at this crime scene, which appears to be a living room with a white couch and clean white wallssave for the areas where blood was spattered during the crime. Using laser scanning technology to determine bloodstain origin. The hit showtime series dexter centered on a blood spatter analyst for. Blood stain pattern analysis research paper 1749 words. If they where running then therell probably be a long tail. Properties of blood blood is a fluid with its mayor biological, chemical and physical properties which must be taken into account when. Additionally, the program will furnish veteran officers with advancement opportunities available through specialized education in crime scene. Learn how csafe is using statistical modeling software to gain a better understanding of how blood behaves, and more about a new blood spatter database designed to test analysis methods in. Bloodstain pattern analysis uses an analysis of the color, shape, and size of blood stains at a crime scene, as well as principles of fluid mechanics and biology to draw conclusions about the nature and proceedings of a crime scene.
Visualization of castoff patterns using 3d modelling software. Heres hoping that we all work together and continue to grow. Sometimes, software specifically designed to aid in bloodstain pattern analysis, such as hemospat, is used. The stains would be going in a straight line with the tail pointing where they were coming from. Also known as bloodstain pattern analysts, you may be able to find. Reliability assessment of current methods in bloodstain.
Blood stain pattern analysis by dana elalfy on prezi. Communicating conclusions in bloodstain pattern analysis. In bloodstain pattern analysis bpa, this involves the transferal of ideas regarding pattern classification and reconstructive meaning from the mind of the analyst to the minds of others. Interpreting these stains in terms of how they were made, what type of weapon was used to make them, the speed at which blood left the body, and the degree of force used to create the spatter pattern is the top priority of onscene bloodstain pattern analysts. Dexter the real blood spatter detectives short documentary. Chu is the innocence project forensic policy associate, and if anyone could tell me the truth about bloodstain pattern analysis, it would be her. Like a real blood spatter analyst, dexter is sometimes at the scene of a crime collecting blood samples, sometimes sitting in a lab looking at a screen of data or even testifying in court as an expert to solve various crimes.
Forensics expert explains how to analyze bloodstain patterns wired. Although important aspects of bloodstain pattern analysis are well supported by research. Blood as an important tool in criminal investigation. Bloodstain pattern analysis is conducted by trained and skilled analysts who have completed the isp bloodstain pattern training program. When bloodstain patterns are found on the crime scene, the investigator wants to know where it came from, or more precisely, where the victim was. Use of the backtrack tm computer program for bloodstain pattern analysis of stains from downwardmoving drops. Real crime scene investigation of blood splatter patterns. However, this technique can take place only once analysts grasp certain other aspects of the bloodstains. Passive is when a person has a cut or stab and it drips.
As blows are struck into liquid blood, impact patterns are created, with blood droplets by their shapes and directional trails creating elliptical stains that can be analysed to determine the point of origin po. To determine where the blood source was investigators use a straightline approximation for the trajectory, ignoring effects of gravity and drag and thus overestimating the height. Bloodstain pattern analysis is recognized for the value in brings to understanding and describing a bloodletting scene to the investigator and to the court. Bloodstain analysts communicate through written reports or verbal testimony. Although the program has been in use for a number of years, few validation studies have been carried out. We are all encouraged by the good work thats happening in the field. Forensics chapter 10 bloodstain pattern analysis quizlet. How does bloodstain pattern analysis actually work. To apply this method, the researchers created spatter patterns of human blood under controlled conditions. A drop trail pattern is a series of drops that are separate from other patterns, formed by blood dripping off an object or injury.
The most visually striking part of the process, and therefore the one most featured in shows like dexter, is the technique of stringing. Blood dripping down the walls, a victim slumped on the floor. For each of 40 separate blood stains, they determined its width and impact angle, and, using a commercial 3d surface scanner, measured the volume of the stain, from which they found the volume of the original drop. If a crime involves multiple perpetrators, then blood pattern analysis becomes even. Applying software tools to automatically recognize blood stains from a blood spatter image and extract image features to reconstruct trajectory. Physical key facts angles of impact, point of origin, and. The big short 6 jared vennetts pitch to front point partners jenga blocks scene duration. There are wellestablished molecular biology methods for dna identification, and blood pattern analysis can be important for crime scene reconstruction. Last fall, more than three decades after joes conviction, i found myself surrounded by human blood. Bloodstain pattern analysis is rooted in the belief that the drops, spatters and trails of blood at a crime scene are rich repositories of information that can be used to reverse engineer and even. Bloodstain pattern analysis when bpa is done properly, many things can be discerned including distance from the blood source to the target, direction of travel and impact angles, nature of the force used to cause the bloodshed, sequencing of multiple bloodshed events, and interpretation of contact or transfer patterns. Dexter morgan works as a bloodstain pattern analyst or blood spatter analyst, as.
How bloodstain pattern analysis works howstuffworks. If they were walking there might not even be a tail but they know to follow the blood. However, there are significant problems with the techniques currently used to detect blood, and there is no reliable method to estimate the age of bloodstains. Fresh from a night of righteous murder, dexter morgan arrives at a crime scene. In this pilot episode, the purpose of the scene is to establish what dexter does as a bloodstain pattern analyst. The patterns included stains made under a variety of conditions relevant to a crime scene and included some. Seemingly convinced by dexter s skills as a blood spatter analyst, i walked over to sarah chus office to do my own investigating. There are probably many people who decide on a career field based on what they see on television. I had signed up for a class in bloodstain pattern analysis in the hope of gaining a better grasp of both bloodstain interpretation and the training police officers receive in the discipline. The backtrack program for bloodstain pattern analysis is an excellent forensic tool that allows bloodstain pattern analysts to simply and quickly analyze patterns of projected bloodstains at bloodletting crime scenes. How a dubious forensic science spread like a virus propublica. Blood spatter model to help crime scene investigation.
It could also be from another weapon and the surface it hits will effect it alsotransfer is when one blood soaked object smears that blood on another object or surface. Find the perfect college and scholarships to pay for it. Experts in the field often say that its as much an art as a science. The agent had a 25year career as a blood spatter analyst, but was fired from the sbi in 2011, as wral reported, after an audit discovered that he had falsified evidence in 34 different cases. How to become a blood spatter analyst criminal justice. It gave bloodstainpattern analysis its first toehold of legitimacy in texas courts.
The evolution of bloodstain pattern analysis verdicts in. Are there any accurate portrayals of careers, or is it all beautified garbage. The method seeks to answer the question of how blood travelled through a given space to leave stains on a surface. Also, a passive stain might spatter around if it hits concrete or any surface that isnt smooth.1603 1413 1640 198 369 884 588 663 733 1580 1036 792 656 486 315 1648 680 296 1281 792 1162 1380 579 371 1550 1616 974 858 925 187 994 1601 807 592 517 1059 1041 586 1435 1345 1284 1143 694 836 1332 240 1151