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Blood Stains

The Forensics of Blood

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After a homicide or an assault has been committed, police investigators usually find blood at the scene of the crime, giving them clues as to what happened. The blood’s texture and shape and how it is distributed around the victim often help investigators determine when the crime was committed, whether the crime was preceded by a fight between individuals, and which weapon was used say, a knife, a gun, or an object used to hit a person. But criminals have tried many ways to hide, clean up, and remove blood evidence. For example, what looks like blood may be another substance placed there by the criminal to mislead police investigators. Also, some criminals clean up the blood from the crime scene or move the victim’s body somewhere else, making it harder to reconstruct what really happened. To take these potential scenarios into account, forensic scientists who apply the latest scientific discoveries to law have developed techniques that can tell whether the

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A Preliminary Validation of the Use of 3D Scanning for Bloodstain Pattern Analysis

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Abstract

3D scanning technology is beginning to be used more commonly to record crime scenes. Besides being able to document the scene and the locations of evidence within it, 3D scanners and associated software can now be used to analyze impact bloodstain patterns. In the present study, two “doubleblow” impact patterns were created in a classroom setting for analysis using both the HemoSpat bloodstain pattern analysis software and the FARO Focus3D scanner with FARO Scene software. Both methods produced area of origin results that were acceptably close to the actual initial blood source location.

Introduction

Impact bloodstain patterns, created when a blow is struck, can sometimes be analyzed to try to determine the approximate location of the source of the blood [1]. With this information in hand, an investigator can try to determine what might have occurred at the scene of the crime. Blood source areas of origin may indicate...

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Using Infrared Photography to Document Clothing Evidence in the Reconstruction of a Homicide

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Background on Infrared Photography

The use of infrared (IR) photography in forensic casework has been well documented in the forensic literature. It has primarily been used for the documentation of gunshot residue patterns and blood staining on dark colored clothing (1, 2), although it has also been used for the photography of latent tattoos and for the characterization of different types of inks. The principle behind the infrared photography of blood stains is that many dyes and fabrics reflect a large amount of infrared radiation, whereas blood stains absorb most wavelengths of visiblelight (400-700 nm) and near infrared light (700-900 nm). This results in the fabric appearing gray or white with the contrasting blood staining darker in color. The enhanced contrast between the fabric and the evidence (blood) allows the examiner to better interpret the evidence and assists in sample selection for further testing (i.e. phenolphthalein, DNA). This technique is especially useful due to its non-destructive nature, its lack of

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Bloodstain Patterns

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Blood spatter patters, at the scene of a violent crime can indicate how the crime occurred. The shape of spots of blood can be used to determine an estimate of their velocity and/or impact angle and/or distance fallen. Elongated portions of the blood spatter indicates the direction that the blood drop was traveling when it impacted the surface.

Some of the variables used in blood spatter analysis are:
• Size of the blood spot
• Quantity of blood
• Shape of the blood spot
• Distribution of the blood in the crime scene
• Location of blood stains
• Angle of impact
• Texture of target surface
Blood that drips vertically from a stationary source onto a smooth, hard, flat surface is usually circular with crenated edges. Rough surfaces result in more spatter. (See Figure B-2) The shape of a bloodstain indicates its direction of travel. Such bloodstains are shaped more like an exclamation point where the shape and length indicate

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Bloodstain Pattern Analysis Involves The Scientific Study Of The Static Consequences…

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A. INTRODUCTION

Bloodstain pattern analysis involves the scientific study of the static consequences resulting from dynamic blood shedding events. A detailed study of bloodstain patterns at crime scenes often develops invaluable evidence. The distribution, size and shape of bloodstains on a victim, on a suspect, or on the walls, floors, ceilings, or on objects at the scene can help reconstruct these blood shedding events. Bloodstain pattern analysis can also help one evaluate the credibility of statements provided by a witness, a victim, or a suspect. Physical evidence waits to be detected, preserved, evaluated, and analyzed. Herb McDonnell once said that in the course of a trial, both defense attorneys and prosecuting attorneys may lie, witnesses may lie, and the defendant certainly may lie. Yes, even the judge may lie. Only the evidence never lies. But if the evidence is not properly recognized, documented, preserved, and processed, all we have are attorneys, witnesses, defendants, and judges. Enough said.

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Blood on Black- Enhanced Visualization of Bloodstains on Dark Surfaces

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Abstract

Accurately visualizing and documenting bloodstains and patterns is an integral part of crime scene investigation and can provide crucial information for both the analysis of evidence in the laboratory and crime scene reconstruction efforts. Visualization of bloodstains is trivial on white or lightly colored surfaces. However, on darkly colored or black surfaces, this visualization can be extremely difficult. The failure to visualize and thereby recognize blood and bloodstain patterns on darkly colored surfaces has had seriously adverse consequences for important criminal investigations. There are two aspects to the problem. First, the presence of blood may not be recognized at critical stages in the investigation. Second, where the presence of blood is recognized, the pattern of blood-staining may not be appreciated. Sampling of bloodstains for DNA typing and other analyses must take place with knowledge of the bloodstain patterns. Otherwise important information may be destroyed. In a significant number of cases knowing how the bloodstains were formed

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Determination Of Time Since Deposition Of Blood Stains

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Introduction

DNA analysis has revolutionized the field of Forensic Science by allowing for unambiguous identification of the person from whom a biological sample has been obtained. DNA provides a spatial link between a suspect and a crime scene or other location relative to a crime investigation. In many instances, this information is sufficient for conviction of the perpetrator of a crime. The limitation of traditional DNA, however, is that it provides no information on when the biological material was deposited. It only indicates that, some time in the past, the person visited the scene, it could have been months or years before the material was collected. Temporal linkage between the biological material and the commission of a crime is especially important in situations involving victims and suspects with close personal ties. In these instances, finding biological material from the suspect in the home or other pertinent location associated with the victim is not unexpected....

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Bloodstains

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Bloodstain pattern analysis is a forensic discipline that deals with the physics of the blood and assesses bloodstains left at crime scenes using visual pattern recognition. It is used to shed light on various forensic matters including reconstruction of events, differential diagnosis of homicide/suicide/accident and identifying areas with high likelihood of offender movements for taking DNA samples. There are documented descriptions of bloodstain shapes at crime scenes that date back to past centuries. However, it was the Samuel Sheppard case in the USA that prompted advances in this f ield. Bloodstain pattern analysis is employed worldwide by scientists, police off icials and medics in an interdisciplinary manner. Both the blood itself and the surfaces on which the bloodstains are found are important in the assessment of bloodstains. The umbrella organisation for bloodstain pattern analysts is the International Association of Bloodstain Pattern Analysts (IABPA), which offers various forms of membership. The name of the method (bloodstain pattern analysis) is often abbreviated to BPA.

Additional Resource: Introduction to Bloodstain Pattern Analysis (2204 downloads )

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Determination of Time Since Deposition of Blood Stains

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Introduction

DNA analysis has revolutionized the field of Forensic Science by allowing for unambiguous identification of the person from whom a biological sample has been obtained. DNA provides a spatial link between a suspect and a crime scene or other location relative to a crime investigation. In many instances, this information is sufficient for conviction of the perpetrator of a crime. The limitation of traditional DNA, however, is that it provides no information on when the biological material was deposited. It only indicates that, some time in the past, the person visited the scene, it could have been months or years before the material was collected. Temporal linkage between the biological material and the commission of a crime is especially important in situations involving victims and suspects with close personal ties. In these instances, finding biological material from the suspect in the home or other pertinent location associated with the victim is not unexpected.The reverse can also be true, for instance

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Intimate Partner Stalking and Femicide: Urgent Implications for Women’s Safety

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INTRODUCTION

Stalking, as defined in the National Violence Against Women (NVAW) Survey, includes repeated (two or more) occasions of visual or physical proximity, nonconsensual communication, or verbal, written or implied threats that would cause fear in a reasonable person (Tjaden & Thoennes, 1998, 2000). Using this definition, the results of the NVAW telephone survey of 8000 U.S. women and 8000 U.S. men found 1% of the women and 0.4% of the men reported being stalked during the preceding 12 months. Eight per cent of these same women and 2% of the men reported life-long prevalence of stalking (Tjaden & Thoennes, 1998, 2000). The NVAW survey confirmed that most female victims know the stalker; strangers stalked only 23% of female victims. Overall, 62% of female victims were stalked by a current or former intimate partner, with 38% of the women reporting stalking by current or former husbands, 10% by current or former cohabiting partners, and 14% by current or

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Documenting Bloodstain Patterns Through Roadmapping

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An accurate and methodical technique for documenting bloodstain patterns is invaluable in crime scene analysis.

As the old adage goes, “a picture is worth a thousand words.” However, in the field of crime scene investigation this saying should be changed to “a properly taken picture is worth a thousand words.” Never is this more true than when documenting bloodstain patterns at a scene. Proper documentation of a crime scene, and bloodstains specifically, verifies the integrity of the scene and the evidence within it; provides quality presentations for subsequent courtroom testimony; and allows for outside analysis by other experts.1 The fundamental goal of documenting bloodstain patterns is to accurately depict the patterns as you found them. This is accomplished through note taking, sketching, and photography. Additionally, videotaping may be helpful depending on the scene, but it should never replace photography.

Let’s first address note taking. Your notes should...

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A New Look at Bloodstains Is Changing Forensics

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The rolling pin is traditionally seen as a woman's tool. She can use it to roll out dough -- or to smash her husband's skull.

 The latter tends to be rather bloody, so it's no surprise that the seemingly harmless kitchen utensil is part of the equipment at Germany's only institute specializing in bloodstain pattern analysis, where it's stored between blood-splattered pieces of paper.

The lab uses very little high-tech and modern equipment. Inside the old barn in Usingen, a town in the western German state of Hesse, the creative chaos of a workshop prevails. Much of the equipment seems to have come directly from a hardware store.

Dr. Silke Brodbeck, the director of the institute, turns out not to be a morbid forensic scientist but a tidy and introspective woman. Brodbeck regularly assembles medical experts and criminologists in the barn for demonstrations in the art of interpreting bloodstains and blood...

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Following Blood Trails: A SAR Perspective

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Authors „ Unless otherwise noted, this presentation is based upon the research and field work of Mark Gleason and C. Steve Frye. The presentation was created by Mark Gleason.

„Both are members of the Virginia-based Search and Rescue Tracking Institute (www.sarti.us). „ This presentation may be used by others for educational purposes, with proper credit given to the authors or referenced sources.

Credits and Thanks

„Photographs on slides 19-22 are used with the expressed permission of Joe Slemko, of J. Slemko Forensic Consulting. email: jslemko@bloodspatter.com; website: www.bloodspatter.com

„Poke Week photograph from Kevin Brewer. Information regarding the properties of blood, wounds, and blood clotting was obtained, in part, from discussions with Dr. K. Miller, Search and Rescue Tracking Institute. „ Information regarding types of wounds and resulting blood trails are from the work of Tyron J. Cunningham from his 2004 publication entitled, “Scout Craft and Scout Tracking...

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