DETERMINING DISTANCE BETWEEN SHOOTER AND VICTIM USING BLOOD AND BACK SPATTER PATTERNS

Transcription

1 Michigan-Ontario Identification Association Newsletter October 2012, Issue 10 PEER REVIEWED DETERMINING DISTANCE BETWEEN SHOOTER AND VICTIM USING BLOOD AND BACK SPATTER PATTERNS JULIE CLAYBORN NATIONAL UNIVERSITY (Direct any inquiries regarding the article to the author: ABSTRACT This project was developed in hopes of being able to answer questions about a crime scene that have not yet been answered. Blood pattern analysis is a crucial part of crime scene reconstruction. Analyzing the blood spatter left behind at most crime scenes allows for investigators to determine where the victim and the assaulting weapon came into contact with each other, also known as the point of convergence. They can also tell what type of weapon the assailant used to commit the crime with by analyzing the velocity of the spatter. However, a phenomenon known as back spatter analysis or as blow back analysis may also be left behind and studied by the investigator. The intention of this research is analyzing back spatter of objects shot with three different weapons at varying distance. Different ammunition will also be used. The weapons will be a Walther P22, 9mm Walther PPS, and a.380 Smith & Wesson Bodyguard using Critical Defense hollow point rounds from varying distances. Hopefully, with this study investigators may have an idea how to analyze back spatter to convince a jury that a suspect is guilty or innocent. Background of Study: Blood spatter and back spatter are two groups of the same family; they are all blood stain patterns and can be analyzed like other trace evidence in a crime scene. Crime scenes can tell a story if the investigator knows how to read the evidence, and sometimes they look right over the obvious. Blood stain patterns, especially back spatter can tell what happened and who was at or not at a crime scene. The usefulness of back spatter can be very important in proving or disproving a suspect or person of interests alibi. It may also be a crucial step in proving guilt or innocence in trail. were not at the crime scene, however, if the back spatter is looked at, and the clothing and objects surrounding the place where the suspect was standing it may be able to determine if the suspect was in fact at the scene, and if they were in close contact with the victim. Purpose and Objectives of the Study: The purpose of this study is to ascertain if back spatter and blood spatter analysis can determine the presence and distance of a shooter to the victim. This study is going to look at the physics of blood as a liquid, the angle and velocity of impact of blood on a contact surface, and different contact surfaces that can affect blood spatter. This study will also look at the back spatter or blow back of the blood as a bullet penetrates the victim to determine the distance at

2 which there is no possible way to tell if the shooter was near the victim when they were wounded. There will also be an experiment conducted at which there will be three targets shot, and the blow back patterns are looked at. There will be three different pistols, all shooting from three different pre-determined locations at the target. The objective of the experiment will be to determine by looking at the back spatter distance in front of the target to determine if there is a way to tell the position, presence, and distance from the shooter to the target. Rationale of Study: The rationale for this research is to be able to decrease the need to rely on alibis from suspects, especially if there is also other evidence tying them to a scene. There are too many guilty people walking free because the jury believed they were either not at the crime scene or so far away they could not have been the person holding the gun. This research will hopefully give investigators and forensic scientist yet another tool to use when reconstructing a crime scene and finally getting the story right. Definition of Terms: Angle of Impact-the angle of blood as it strikes contact surface. Back spatter (blow back)-blood that is directed back to the source of the energy or force that caused the spatter Blood spatter analysis-the diameter and shape of blood splatters, which reflect the origin and trajectory of external blood flow in the context of homicide or violent death, in which the skin surface is disrupted. Caliber- 1) the size of a bullet or shell as measured by its diameter. 2) The diameter of the bore of a gun, usually measured in hundredths of inches or in millimeters. Cast off blood spatter- spatter that is created when blood is thrown or flung of an object in motion. Combination spatter- includes both impact and projection spatters. Result of the force of the attack being projected by arterial bleeding, expirated blood, or cast off blood spatter. Expirated blood spatter-the result of spatter expelled from the nose, mouth, or wound that is propelled by the force of air pressure. Forward Spatter-blood which travels the same direction as the source of energy or force which created the spatter, the source of spatter at a rate of more than 100 feet per second. The spatter tends to be very small usually less than one millimeter in diameter and appears mist-like. Impact spatter- occurs when a foreign object impacts a source of spatter. Low velocity spatter- the result of an object striking the source of spatter at a rate of less than five feet per second. The impact results in larger spatters that measure typically in the four millimeter or greater range. Medium velocity spatter- the result of an object striking the source of spatter at a rate of between five and 100 feet per second, the spatter typically ranges in size from one to four millimeters in diameter. Point of convergence- a two-dimensional picture of the point where lines or string track the pathway of two or more spatters meet. Point of origin-a three-dimensional picture of the point where lines or string track not only the pathways of spatter, but also the angles of impact of two or more spatters Porous- having small holes in which liquid or air may pass through. Projection spatter- the result of arterial bleeding cast off blood, and expirated blood spatter strike a surface. Satellite spatter- small droplets of blood that are distributed around the perimeter of a drop or drops of blood and were produced as a result of the blood impacting the target surface

3 Terminal Velocity- maximum speed of free fall of a liquid Viscosity- the internal friction of a fluid which makes it resists flowing past the other layers of the fluid. Void pattern- an absence of blood spatters in an area where you would otherwise expect to find them. Limitations of the study: The most important limitation of the study has to use a substitute substance to represent the blood. This limitation could hinder the way the liquid will spatter on a surface. A second limitation is not being able to use actual cadavers. This could also have a negative impact on the research because of the way the bullet will penetrate the objects that are being used. A third limitation has to work in a controlled environment, severely hindering the way an actual victim would move around an environment if they were being attacked. This study will be conducted on stationary objects. Financial and material means will also hinder the study; this is because there may not be enough data produced to render a pattern that will properly analyze the study. Smaller limitations would be a misfired weapon, which of course is easily remedied by clearing the weapon and re-discharging the bullet and the possibility that no spatter will be created in the study. This final limitation would render the research useless and unusable. Theoretical Framework: The theory behind the intended research is to be able to explain the way investigators use blood stain pattern analysis to reconstruct a crime scene. This could give a lot of information about what happened during the commission of a violent crime such as a shooting death. This information in theory can be used to determine the way a victim moves around a scene as the attack is taking place, and may be even able to provide the distance and location of the suspect as he commits the crime. Research Hypothesis: There are three possible hypotheses that this research could prove. Hypothesis 1: By analyzing the back spatter created by a bullet striking a victim then the distance between the shooter and victim can be determined within certain limitations in distance. Hypothesis 2: The second hypothesis is that the caliber of the weapon will play a significant role in the amount of spatter that will be produced when the target is struck. Hypothesis 3: Neither forward nor back spatter will give any information on the distance between the assailant and target. History of Blood Pattern Analysis: Blood stain pattern analysis is the study of the shapes, categories, and distribution of blood stain patterns in order to interpret what really happened at a crime scene, and can give a plethora of information about the events that took place when examined by an experienced analyst. This information can then be used to reconstruct the crime scene and either lends credibility to witness statements and suspects or either discredits them. This unique technique of blood stain pattern analysis and the use of the scientific method can be the main keys into gaining helpful insight into a series of events that may have happened in the commission of a crime (Kuntz et. al, 2011)

4 The first examinations of blood shapes and patterns were first done in Then in 1905, the possibility of crime scene reconstruction using the blood patterns found were discussed and became a possible reality. Further investigations in 1914 began to then look at how gravity affected the blood patterns when they fell from a significant height (Kuntz, et.al, 2011). In reality the experience of a trained investigator is essential in the basic knowledge of the way blood stain pattern analysis can play a role in crime scene reconstructions. A detailed system of various bloodstains and their origins on a crime scene is helpful for reliable subsequent blood pattern analysis interpretations (Kuntz, et. al, 2011). Physics of blood as a liquid: To understand blood pattern analysis, a person must understand the physical properties, or physics of blood as a liquid. To do this you must be able to understand the effects gravity has on blood, surface tension, and the viscosity or the internal friction of a fluid which makes it resist flowing past the other layers of the fluid (Lee, 2001). This understanding of the physics of blood as a liquid is really no different than that of water in the way it pours, splashes, and spatters. However water is colorless, while bloodstains usually have a color and will contrast greatly over their background surface (Spitz, W., 2006). The temperature of the blood may also affect the viscosity of the liquid. It has been shown that as the temperature of the liquid increases the surface tension will decrease, and the viscosity will also decrease. The study of bloodstain pattern analysis is usually concerned with how blood reacts once it has left the body. When this happens the blood as a liquid usually follows the simple physics of a liquid, or more specifically that of ballistics or the study of projectiles in motion (Fisher & Spitz, 2006). Blood like all liquids is held together by a cohesive force that produces a surface that is resistant to penetration or separation. This phenomenon is known as surface tension of the liquid. The tension will produce a force across the surface of the liquid that will decrease its surface area. An excellent example of this would be as blood leaves the body and forms a spherical shape in the air to minimize the surface area. This is not like the well known pictures of raindrops in a teardrop shape that so many artists will render it as (Fisher & Spitz, 2006). The second physical property of liquids is that of viscosity. Viscosity allows the flow of the blood to decrease as its viscosity increases. Research has shown that when blood drops from a part of the body like a fingertip, it does so in a uniform pattern. In order to produce a drop, the blood volume will increase on the fingertip for example, until the weight causes it to fall from the other blood that has accumulated at this source. Therefore, the gravitational attraction for the drop must be greater than the blood s surface tension. However, since the blood s surface tension is the same at any given temperature, each drop that falls must have a corresponding volume. This volume for blood is typically approximately 0.05 ml or 50 micro liters. If the bleeding is increased, the volume may increase slightly, but the slower bleeding does not result in a drop of volume. The surface area of the object onto which the blood drop hits may determine the size of the drop as well. It should be remembered that the smaller the droplet size the greater is its surface area and, therefore, the slower it will fall (Fisher & Spitz, 2006). A typical drop of blood will not disperse into many drops of liquid as it falls through the air. If the blood breaks up it must first come into contact a rough or dirty surface, or some outside physical force such as an impact causes it to spatter. The degree of blood spatter that comes from a single drop falling onto some type of surface is usually characterized as an inert drop hitting a target or the surface it happens to land on (Spitz, W., 2006). Target Surface effect on Blood Spatter:

5 Surface texture can play a vital role in the study of blood stain pattern analysis. The surface that a drop of blood hits can impact the shape of the spatter it produces. When a drop of blood hits a hard or non-porous surface, such as glass or smooth tile squares, it results in fewer spatters. If the drop hits a rougher surface such as carpet or wood, it will usually result in an irregular shaped stain that has serrated edges and possible has satellite spatter around it (Saferstein, 2011). If the blood drop happens to land on a porous surface, like raw wood or asbestos board for example, there will be fewer spatters produced. This may contrast with the blood drop falling on a paper towel whose surface is both porous and rough in texture. Therefore, consideration of surface texture is a key observation when determining the characteristics of the blood spatter (Fisher & Spitz, 2006). Bloodstain Characteristics: As a drop of blood falls it will reach what is called terminal velocity, or the maximum speed at which the liquid will fall. The terminal velocity of a drop of blood is about 25 feet per second, but only if it is falling from a height of about 20 to 25 feet. The circular pattern that is produced by the drop of blood will increase in size when it falls from the range of one inch to seven feet, however after the range of seven feet the size will not significantly change (Lyle, 2004). When a drop of blood falls and strikes a surface, it is known to splash in all different directions in a circular pattern around the point of impact. The size of the spatter pattern will depend on how high the drop falls from, what the speed of the drop was at the time of impact, and the type of surface that it falls on. Also, of importance are the size of the drop and the angle of impact at which it strikes the surface (Lyle, 2004). The surface that blood hits can change the shape and size of a spatter significantly. Hard and smooth surfaces will tend to create a spatter pattern that is much smaller than the rough or irregular shaped surfaces like wood or concrete. Secondary or satellite spatter is often created when a drop falls to a hard surface. These small secondary drops will surround the original circular stain. When these droplets hit the surface at angles that are less than 90 degrees, the secondary stains are elongated out and the satellite droplets tend to point toward the direction from which they came, not the direction they were traveling (Lyle, 2004). When a drop strikes a smooth surface at a right angle or 90 degrees, it will produce a spatter that is an even circle around the point of impact. If however the blood strikes at a smaller angle, the spatter will created an elongated pattern that looks similar to the exclamation point, with the narrow end pointing in the drops direction of travel (Lyle, 2004). The shape of a resulting bloodstain is often changed when the angle at which it impacts a surface is changed. As the angle of impact is smaller, the bloodstain will become more elongated, elliptical, or oval in shape (shown in illustration). The impact direction of the blood spatter can also be determined by looking at the shape of the stain. If the stain is elongated or elliptical in shape, the tail end or the narrower end of the stain will generally point to the direction of travel of the blood drop. Also as a result of this, the origin of the blood drop can also the spatter and is determined when the angle of impact and direction of travel of the blood drop is looked at in comparison (Lee, 2001). The angle of impact of blood spatter is the angle of the blood as it strikes a contact surface. This angle can be determined by taking measurements of the length of the bloodstain and the width of the bloodstain. There is a trigonometric relationship between the ratio of the long axis known as the length of the stain or v, the short axis or the width of the stain Illustration-1

6 Illustration of impact angle patterns adapted from Henry Lee s Crime Scene Handbook. (Lee, 2001) This ratio can then be measured to come up with an angle of impact for the spatter. The results for coming up with the angle of impact can be determined using a simple trigonometric formula: Illustration-2 Sine of Impact Angle=Width of bloodstain/length of Bloodstain: Illustration shows an example of the calculation of an impact angle of a blood drop (Lee, 2001). Blood trails are often found at crime scenes and careful examination of these trails will provide information about the direction of travel and the relative speed at which the person was traveling. The individual bloodstains will show the directionality characteristics of elongation of the blood stain and the distance between the individual blood stains will be significant in showing the speed of travel of the bleeding source. For clarification, as the speed of the

7 traveling source of bleeding increases horizontally, the more elongated the shape of the stain pattern will be and the distance between bloodstains will also be increased (Lee, 2001). Types of Spatter: One of the most common types of spatter found at any crime scene is impact spatter. The pattern occurs when an object impacts a source of blood. The spatter is then projected outward and away from the source (Saferstein, 2011). There are basically three forms of spatter created when blood is affected by an outside source. The first type is what is referred to as forward spatter. Forward spatter is caused when blood travels in the same direction as the energy or force that caused the spatter to begin with (Kunz, et al., 2011). Forward spatter that comes from gunshot wounds usually come from the exit wound side. As the projectile exits the body, blood will spatter forward until it impacts on an available surface. This spatter will be important during crime scene reconstruction in order to determine point of convergence and point of origin of the blood spatter (American Institute of Applied Science, 2003). When a gunshot wound is suffered, blood and some tissue can be expelled back toward the firearm and the person holding it. This kind of pattern is known as back spatter patterns or blow back. The use of blow back patterns has been used to infer the relationship of an assailant to the target in relation to distance or vicinity (Baldwin, et. al, 2010). As a person or object has suffered a gunshot impact, sometimes there is an expirated blood pattern that results. This pattern results as the air pressure from inside the wound forces blood out, and is usually known by the bubbles in the blood stain pattern. This type of spatter will come from a person who blows blood from the exhalation of air from the mouth or nose. Even if the blood does not come from the nose or mouth, they may originate from possibly neck vessels or the trachea if they are damaged. The expirated pattern is often known by the nebulizer effect that it shows or a mist like pattern, or if the stains are bigger and of an irregular pattern it could be resulting from the victim coughing or a sudden exhalation of air (Kuntz, et. al, 2011). Illustration-3 Illustration of expirated Blood Stain Pattern, Adapted from How stuff works.com Impact Spatter Speeds: Investigators classify projected blood spatters, or blood spatter that is thrown from its source in three different ways. The first classification is called High velocity spatter. These types of spatters occur when an object strikes a target at a speed faster than 100 feet per second. The size of the resulting spatter is usually very small, less than 1 mm in diameter, and appears as a mist like pattern. High velocity spatter patterns can be caused by a bullet being projected at a high speed, and can be seen near entrance and exit wounds (Lyle, 2004). Illustration-4

8 Illustration of High Velocity Impact Spatter, Adapted from usaschool.us. This type of spatter is normally produced when a force, other than gravity, strikes a target at a speed of at least 5 feet to 25 feet per second. This type of spatter will usually cause blood to break into smaller droplets ranging in size from 1 mm to 4 mm in size (Lee, 2001). However, smaller or larger size stains are possible, these are known as combination spatter, and can be the result of a victim being stabbed in the chest or neck producing expirated blood patterns or cast off patterns on nearby walls or ceilings (Lyle, 2004). Illustration-5 Illustration of medium velocity blood spatter, Adapted from The third type of spatter normally found is low velocity spatter. This type of spatter is produced when a force strikes an object at a relatively slow speed, normally 5 feet per second or less (Saferstein, 2011). This type of pattern is normally seen as a splash pattern or a large pool of liquid. They may also have large droplets surrounding the main stain. These splash patterns

9 are not normally seen at a typical crime scene, though they can be seen if the victim with a wound has had a glancing blow or surprisingly in suicide victims involving head wounds where the victim is in an upright position. The investigator should also be weary of low velocity spatter as well, as they are also seen in staged crime scenes as well. Illustration-6 Illustration of Low Velocity Blood Spatter, Adapted from HowStuffWorks.com Points of Convergence and Origin: When a body is subjected to a force strong enough to cause a significant amount of bleeding, the blood released will hit different surfaces at a variety of different angles. This can be used to determine the point of convergence of the blood spatter. The point of convergence is a common point in which all the individual bloodstains can be traced. All the blood stains when measured along their longest axis or the length of the stain, will come together at a point on that surface, also showing the direction from which they came and their direction of travel. For example, if there are several blood stains on the floor, the various stains can be measured and followed along the length of the stains, and all the lines will come to a common point. It is at this point where all the lines will intersect and the point of convergence is found (Becker, 2009). The point of convergence will also assist in determining where the blood came from or the point of origin. The point of origin will give a three dimensional picture at which the body was located when it was struck and began to give off drops of blood. The point of origin can be determined by projecting angles or impact of a bloodstain back to an axis that is made through the measured point of convergence. To put this more simply, the point of origin is made by the point of convergence showing the general direction the blood traveled. By examining the blood stain, a distortion can be seen in the shape of the drop due to the angle at which the blood hit the surface. This distortion can reveal the impact angle of the blood and by using strings projected from each measured bloodstain at its angle of impact back to an axis that is perpendicular to the surface on which the bloodstains are located and is passed through the point of convergence. The place where these strings intersect will show a point in a three dimensional space from which the bloodstains is likely to have originated from (Becker, 2004)

10 Illustration-7 Illustration of point of convergence adapted from Henry Lee s Crime Scene Handbook. (Lee, 2001) Interpreting Void Patterns: A void pattern is the absence of bloodstain spatter in an area where a normal person would otherwise expect to see them. Often times this pattern indicates where the attacker stood because his body prevented the blood spatter from reaching the surfaces behind him. For example, if a shooter attacks a victim and a gunshot wound is suffered, there would most likely be a back spatter from the force of the bullet entering the victim causing blow back from the wound. This back spatter would most often land on the assailant, blocking the spatter from reaching the surface he is standing in front of. Finding this spatter on the clothing or body of the suspect, or on the firearm in possession of the suspect could confirm that the suspect was on scene at the time of the attack. Finding the spatter on the suspect and a matching void at the scene could prove that the suspect was in close proximity to the victim at the time of the attack and may disprove the alibi given by the suspect that he was not on scene. However, stains found on someone who came along after the attack and accidently got blood on his or her clothing wouldn t show a spatter pattern and would therefore not match a void pattern at the scene. Again this helps investigators confirm or refute the statements given by a suspect that he was or was not at a scene (Lyle, 2004) Illustration-8 Illustration of a Void Pattern in blood, Adapted from HowStuffWorks.com

11 Reconstructing the Scene Using Spatter Analysis: As an investigator reaches a scene where he knows there will be blood evidence, he must then start to protect himself and other officers from any blood borne pathogens that may be present. The first thing before entering any crime scene where blood evidence is to be collected or encountered is to use universal precautions. The collection team must wear rubber gloves, protective clothing; Tyvek suits for example, and protected goggles to prevent any transmission of disease and also to protect the scene from contamination (Fisher, 2000). Investigators should start the reconstruction by first preserving the scene and the evidence. Often time s investigators will photograph the scene with overall camera shots, medium range shots to show relationship between objects, and then close up shots to show a specific image of the evidence in question. In photos of blood stain evidence, close range shots are taken to show specific detail of the stain, and then a second shot is taken with a ruler to show the scale of the spatter (Lyle, 2001) As the investigator actually enters the scene he must then start to look for the blood evidence. Sometimes the spatter may be hidden, or the suspect may have tried to clean the scene, therefore ridding the area of any visible blood stain evidence. Many investigators also want to know if what they are looking at is actually a blood stain at all. Therefore, they will perform what is called a presumptive test in the field that can give them that answer (Bennett & Hess, 2004). There are tests that can be done in the field to identify if a stain is blood or not. This test is known as a catalytic test. The most commonly used chemicals to perform this test are o-toluidine, luminol, phenolphthalein and leucomalachite green (Becker, 2004) In the o-toluidine test a reagent is used that is a mixture of o-toluidine and ethanol. O- toluidine drop and 3% hydrogen peroxide droplets are applied to a suspected blood stain. If there is a rapidly developed blue color appears, that is enough information for the investigator to have a strong suspicion that the stain is blood stain (Becker, 2004) Luminol tests are also a popular test used by investigators to find hidden blood stains and to test if they are blood stains or not. The luminol solution is a combination of distilled water, luminol, sodium perborate, and sodium carbonate. Once the solution is sprayed on a suspected spot, a bluish-green luminescence will be scene. This reaction can only be observed by darkening the room and removing any ambient light from the room. The down side of using luminol as a presumptive test is that in some instances it can give a false positive result. This occurs especially in the presence of bleach or toilet bowl deodorizers. However, the reaction will show a distinct difference in luminescence when it is a false positive reaction. These differences could develop in different ways. The color may be different; a light green to white color instead of the blue green seen in a positive reaction. The duration may differ as well as it will produce a very immediate reaction that will die out quickly luminol tends to remain for several seconds after application on a positive result. The intensity of the reaction will also differ. In the presence of bleach, for example, the intensity of the luminescence will be extremely brighter than a positive result on a blood stain (Gardner, 2005). The third test is a phenolphthalein test. When a bloodstain is tested with phenolphthalein with the addition of hydrogen peroxide, the hemoglobin in the blood will cause a very deep pink color to appear. However, this test is not conclusive as other substances will also react the same way with the chemical, but a positive reaction will be strongly suggestive (Becker, 2004) The last test performed in the field to identify a blood stain is the luecomalachite green test. This test uses a low-sensitivity reagent made of 1 gram of leucomalachite green powder, 100 ml of glacial acetic acid, and 150 ml of distilled water, and then the entire solution is

12 diluted with hydrogen peroxide. A positive reaction using this chemical will produce a green color when in the presence of blood (Becker, 2004). Now that the bloodstains have been confirmed as blood, the investigator can then start to reconstruct the scene using the spatter that is found in the scene. Using the point of origin and points of convergence the investigator will be able to determine from what direction and from where the spatter originated from. By using what is called a stringing method, the analyst will extend a string or a rod from each droplet, and by using a calculated method extend the string or rod back to where the point of convergence is figured to be. However, according to some analyst the stringing method has proven to be unreliable because if there is even on odd spatter pattern it could through off the whole reconstruction. Therefore, forensic computer software has been developed in order to make the analysts work faster and more reliable. With most of these programs the length and width of the stain is entered into the programs calculator and that will then produce a three dimensional interpretation of the point of convergence and origin. One such program is called No Strings Attached, and has been used in several cases to predict and calculate points of convergence and origin (Fisher & Nickell, 1999). Also by using the shape and size of the spatter and a simple trigonometric calculation to obtain an angle of impact, the investigator can piece together the movements of the victim if he is ambulatory while losing blood. The presence or absence of back spatter may also be of use to the investigator as in could determine where the suspect was in relation to the victim at the time of the attack. If there is a void pattern, and the matching spatter is found on the clothing of a suspect this could put him in close proximity to the victim when the wound was received (Lee, H, Miller, T & Palmbach, T, 2001). There is a fairly new technique for crime scene reconstruction using blood stain patterns called road mapping. This technique was developed by Toby L. Wilson of the Miami Dade Police Department Crime Laboratory and it allows for complete documentation of bloodstain patterns. This procedure calls for the use of overall, medium, and close up photographs combined with the use of labels and scales. When looking at a group of bloodstains, separate group are identified and labeled. Then the important stains within that group are further labeled and identified accordingly. These labels and scales will serve as the road signs in the photographs and ensure that the person looking at the picture does not get lost at what he or she is looking at. The most important aspect of this technique will allow others to properly analyze the patterns from photographs without ever being present at the physical scene (Winterich, 2009). When using the road mapping technique to reconstruct a scene using the bloodstain patterns it is important to remember that this technique can be used when analyzing stains on clothing as well. However, it is also important to use caution when using road mapping because it is a quite intrusive technique and should only is performed after all the photographs and collected samples have been obtained (Winterich, 2009) The road mapping technique can provide investigators with a simple and systematic method for properly documenting bloodstain patterns while also allowing the investigator to graphically show the relationship between patterns, individual stains, and landmarks within the scene using the photographs taken. By using this method, it will most assuredly allow anyone viewing the photographs, such as several different independent experts, peer reviewers, and jurors, are never confused and are able to make judgments of the scene appropriately (Winterich, 2009).

13 Summary: Bloodstains are extremely common at homicide scenes. Bloodstain pattern analysis is based upon the laws of physics which is well accepted in the scientific community. When blood spatter evidence is encountered is should be relatively easy for evidence found at a crime scene the investigator to analyze and re-create what has happened at a crime scene. However, it is hardly enough to be sufficient enough to paint the whole picture; it will certainly explain certain facets of the scene that may not be clear or misinterpreted. Taken in consideration with other blood pattern analysis should be of a profound assistance in determining what happened during the commission of a crime (Fisher & Spitz, 2006). The role of the investigator is to recognize the blood stains and apply the correct expertise to identify, interpret, and preserve the blood stain for later examination. Bloodstains on clothing can be a way to identify a suspect through the use of possibly back spatter that was expended during the commission of the crime. These stains can also be able to paint the picture of the various movements of the suspect and victim around a crime scene through the interpretation of angle of impact of different spatters found, and also the correct calculation and interpretation of point of origin and convergence which can tell the proximity of the shooter and his victim when the shooting incident took place. Blood spatter analysis is extremely important to the crime scene analysis and reconstruction. If the evidence is present it could be the key to recreating the events of a crime and possibly solving a crime that may be unsolvable with just other trace evidence. Blood spatter, especially back spatter from a gunshot wound, can put the suspect near the victim when the wound was sustained, and in turn can disprove his alibi and possibly end in a conviction in a homicide trial (Fisher & Spitz, 2006). Methodology Setting: This research will be conducted during the daytime hours at a private residence. There will be a firing range assembled with a berm to make sure that the fired rounds are collected and do not go past the firing range. Platforms will be designed to hold the targets and a backdrop as well as paper in front of the target to catch the blood spatter. Description of Research Instruments: Research materials will be gathered at random places. The experiment calls for a total of eighteen targets. This target will serve as a substitute for the human body. The target will be used as a control variable in this experiment. There will also be a blood substitute used. This substitute will be a mixture of Karo brand corn syrup bought at a local grocery store, and red food coloring. The Karo syrup colored red will have a similar viscosity as human blood, this will react a similar way to real blood when struck with an outside force. In addition to the substitutes used for blood and the human body, there will also be three different weapons and different ammunitions used for the tests conducted. The first will be a Walther P22.22 caliber semi-automatic pistol loaded first with copper jacketed bullets then again with hollow-point Critical Defense brand bullets. The second weapon will be a Smith and Wesson.380 caliber Bodyguard semi-automatic also loaded with the same ammunition that coincides with the caliber of the weapon. The third weapon used will be a Walther PPS 9mm semi-automatic pistol, once again loaded with the coinciding ammunition. The research experiment will be recorded with a Canon Rebel EOS digital camera with a lens capable of taking pictures to show the details of the experiment. To measure the distance of the spatter produced a tape measure will be used, as well as a spectacle in order to look at the spatter under magnification, and with a built in ruler to confirm that the spatter is low, medium or high velocity spatter.

14 Procedure and Analysis: This experiment will be conducted using all safety precautions. Ear and eye protection will be worn as will rubber gloves so as not to leave any transfer that might interfere with the experiment. The targets will be placed upon a platform with a backdrop about three to five feet behind it and a forward drop at varying distances in front of them. Each target will be fired at with each weapon and the distance of back spatter will be measured and analyzed for velocity using the measuring instruments. This will be repeated with each target, and then also repeated using different types of ammunition to see if that will have any effect on the type of spatter produced. Type of weapon and different weight ammunitions will be examined to see what effect they have on the target. The effect of the weapon should be that the larger caliber the weapon the more spatter it should produce and at longer distances. Different ammunitions will also be examined in relation to each target. Ammunition acts in different manners when a target is hit. Regular copper jacketed ammunition could go straight through a target producing forward and back spatter, or it could actually be retained inside the target not producing any forward spatter at all only the back spatter. Copper jacketed ammunition is also known to enter a target and bounce around inside the target ricocheting off of bones and other hard surfaces. This causes a lot of damage inside the target, and may not produce as much forward spatter as thought because, if damage is done on the inside in the case of a person, internal bleeding would occur, therefore limiting what forward spatter there maybe. Hollow point ammunition could also react in different ways depending on the target. Hollow points are known to break apart and mushroom upon impact to a target. It is expected that shooting a target with this type of ammunition will produce a large amount of back spatter, however forward spatter maybe limited as the bullet may be retained or broken apart inside the target creating a great deal of damage inside the target. Hypothesis 1: To test this hypothesis three targets will be shot at with three different weapons and different types of ammunition. Back spatter will be produced and measured as mentioned above and the measurements will then be recorded in a notebook used for any notes. The distances of the back spatter will then be averaged together for all weapons and ammunition considered, and then submitted to a chi-square one tailed test to indicate the significance of the data. Any data with a result of <.05 will be considered as significant. Hypothesis 2: To prove or disprove these hypothesis three weapons will be loaded with different types of ammunition and will be fired at three targets from varying distance. Each shot should produce back spatter which will then be measured using the tape measure and spectacle for distance. The information obtained will be gathered and recorded in a notebook for notes. Any data obtained in reference to comparing the distance from both type of bullets to determine the significance of the data. Any data that is <.05 will be considered significant. Hypothesis 3: In order to test this hypothesis the data from the first two hypotheses must be compared and analyzed. If the results are significant and any data is <.05 then this hypothesis will prove to be false. If after comparing the data and any of the results are <.05 then this will prove to be true. If the data proves to be >.05 then the hypothesis will prove to be false and discarded. Each test will be digitally photographed using a Canon Rebel EOS with a fast lens attached. For the purposes of this study, a distance will be determined for the back spatter

15 produced and give an idea of how far away the shooter was from the target when the shot was fired. The results could be arranged in a table that uses type of weapon used and the varying shooting distances as parameters, with the distance of the two for each test being recorded. The results could be expressed in a chart as shown below: Distance Weapons Used 6 feet 12 feet 18 feet.22 cal ndis ndis ndis.380 cal ndis ndis ndis 9mm cal ndis ndis ndis The obtained distances must be converted to a decimal number rather than the standard way of recording distances, for example 5 5 will be recorded as a decimal number such as 5.42 in order for the statistical tests to be done. Because of the multiple sets of data being analyzed, the distances achieved from each pistol and will be averaged together and analyzed by a chi-square one tailed test with 2 degrees of freedom. There will be a total of eighteen test shots in this experiment and a chi-square will be used to test the first hypothesis. The second hypothesis will be analyzed with a student t-test will be created to test for significance. Results The results of this study proved to be varied in statistical significant however, it did show that it may be possible to put a person on a crime scene in general due to blow back spatter. This spatter was found on the person shooting the target multiple times, therefore placing them on scene. Spatter was also found on general witnesses to the study placing them on the scene as well. The first hypothesis in this study was in reference to the distance back spatter was produced when shot at with a.22 caliber semi-automatic pistol, a.380 caliber semi-automatic pistol, and a 9 mm semi-automatic pistol using regular copper jacketed ammunition and hollow point ammunition. It was expected that as the caliber of the weapon increased and at lower distance more back spatter would be produced for the copper jacketed ammunition. It was also expected that with the hollow point ammunition the back spatter could possibly be less due to the fact that hollow points tend to mushroom on impact and stay within a target. Therefore, data was analyzed after being collected in a table to show the results of each test. The raw data was then converted to decimal numeral form in order to statistically analyze the data. After conversation the results according to distance traveled was then averaged together and subjected to a one-tailed chi-square for distance comparison and any data that is <.05 will be considered significant. Table-1 6 feet 12 feet 18 feet.22 caliber caliber mm Results from each test arranged in table form for better understanding. Table-2 6 feet 12 feet 18 feet

16 .22 caliber caliber mm Results converted to decimal numerals for testing. Table-3 6 feet 12 feet 18 feet.22 cal cal mm Table illustrating distance using hollow point ammunition Table-4 6 feet 12 feet 18 feet.22 caliber caliber mm Table illustrating distances converted to decimal numerals for analysis. As illustrated below when each average distance is compared the results are statistically insignificant using the.22 caliber pistol and the.380 pistol using the hollow point ammunition because the results are >.05. However, when looking at the 9 mm pistol average for both types of ammunition and the.380 caliber pistol using copper jacket ammunition distances the results are shown to be statistically significant as the results are <.05. Table-5 Weapon used Data Description DF Results.22 cal copper jacket ammo mean distances of Weapon and ammo at 6, 12, And 18 ft..22 cal hollow point ammo mean distances from Weapon and ammo At 6, 12 and 18 ft.380 cal copper jacket ammo mean distances from Distances from weapon And ammo at 6, 12 and 18 ft

17 .380 cal hollow point ammo mean distances from Weapon and ammo at 6, 12 and 18 ft 9 mm copper jacket ammo mean distances from Weapon and ammo at 6, 12 and 18 ft 9mm hollow point ammo mean distances from Weapon and ammo At 6, 12, and 18 Table showing average distance and chi-square results. This first hypothesis has been proven as statistically inconsistent and therefore disproved. It may be possible to show distance between the shooter and target using the back spatter distances, however due to limitations of the study, there were not enough repetition of tests to show the data as overall significant. The second hypothesis in this study was in reference to comparing the distances of each pistol and each the respective ammunition choice to each other to determine if the distances found are significant. The data was collected and then subjected to a student t-test to compare each pistol using each ammunition to each other, for example the.22 caliber pistol using the copper jacketed ammunition and the.22 caliber pistol using the hollow point ammunition were compared to each other relative to distance to ascertain if the distances are statistically significant. Table-6 6 feet 12 feet 18 feet T-test results.22 cal w/copper jacket ammo cal w/hollow point ammo.380 cal w/copper jacket cal w/hollow point 9 mm w/copper jacket ammo mm w/hollow point ammo Table comparing weapon type and ammunition together at varying distances with t-test results. As shown when comparing the distances with each weapon and ammunition to each other, the.22 caliber pistol and the 9 mm pistol show a t-test result that is >.05. These two weapons are

18 proved to be statistically insignificant when determining distance. However, the.380 caliber pistol comparison is statistically significant, with the results being <.05. The second hypothesis in this study however is proven overall to be statistically insignificant in reference to determining distance. This is due to limitations on the study hindering the repetition of tests to prove a pattern. The third hypothesis is overall considering both studies of weapons and ammunition proves to be true. The results from each study, the chi-square results and the t-test results ultimately prove that in this particular study overall deterring distances are statistically insignificant. The third hypothesis is proven to be true with regards to this particular study. Conclusion, Discussion, and Recommendations Conclusion: This study has given information and statistical data when looking at three different weapons with two types of ammunition and varying distance. The conclusion in this study is that statistically it is impossible to tell the distance between shooter and target using back spatter alone. When analyzing the results of each hypothesis given, there was some significant data with regards to the.380 caliber pistol with copper jacket chi-square test and the 9 mm caliber pistol at varying distance student t-test. These two exceptions had results that are statistically significant in this study with results being <.05. When looking at different circumstances in the tests conducted, back spatter was found to be on the shooter multiple times. This would place a suspect on the scene of a crime, and initiate an arrest. This is vitally important in proving that the suspect is guilty. As Locard's Principle states, at every crime scene something is left and something is taken away (Bennett, W & Hess, K). In this study, back spatter was found to be on the person shooting at the target, this of course would be taken with them from a crime scene. Also, in multiple circumstances, there was also a void pattern that was created as the spatter was blocked by the suspect; this is what is left behind at the crime scene. Discussion: There are many things to consider that could affect the outcome of this study. Every variable of this experiment has error and uncertainty involved in it. Everything from the bullet speed (error comes from round and pistol manufacturing specs), accuracy of the weapon (determined by pistol manufacturing specs), accuracy of the shooter (determined by consistency in trigger pressure, angle, and level of arm and mental fatigue), and consistency of whatever is used to shoot at (bullet kinematics and dynamics will be different depending on the weight, and build of the person shot as well as location shot at) have to be taken into account. This study did not include most of these variables given, so they almost necessitate experiments in and of themselves to figure out the cumulative error and uncertainty inherent in the experimental methodology. When these figures are obtain, it is also necessary to know how they relate to each other and how they will propagate down to the final calculations. Therefore, it is required to obtain more data, and determine experimental error. Then use the data to make a best fit equation for each of the data obtained on each condition. Compare the R-squared values of the best fit lines to ensure that they are within experimental cumulative error. This should be enough to give an empirical equation for each condition of this study experiment. Then by interpreting the best fit equations and analyzing with that, the general empirical equation that contains all of the experimental variables is obtained. Once the empirical equation is obtained, check it against the

19 data collected to make sure that the predicted results are within the errors associated with this experiment. Recommendations: It is the recommendation of this study that further testing be done in order to examine the results accurately. The study should be conducting using each variable of the study in multiple reputation tests in order to see if a pattern in the data is obtained. The test should also have a less controlled environment and more financial and material means to show results that may be statistically significant. Technology is advancing extremely rapidly. Therefore, it may be possible in the future to have a simpler way to determine the distance of a shooter to a victim. This is almost a necessary knowledge in order to place a suspect at the scene of a crime. By analyzing back spatter this could be possible with the right set of circumstances and means available. References American Institute of Applied Science (2003). Significance of Blood in Criminal Investigations: Investigating Bloody Events (1st ed.). Youngsville, North Carolina: American Institute of Applied Science. Baldwin, D., Epstein, B., Laber, T., Taylor, M., & Zamzow, D. (2011). The effect of firearm muzzle gases on the back spatter of blood. International Journal of Legal Medicine, 1(125), doi: /s Becker, R. F. (2009). Criminal investigation (3rd ed., pp ). Sudbury, Mass: Jones and Bartlett Publishers. Bennett, W. W., & Hess, K. M. (2004). Criminal investigation (7th ed.). Belmont, CA: Wadsworth/Thomson Learning. Bowman (2012, September 29). forbloodspatter1. Mrs. Bowman's Home Page. Retrieved July 23, 2012, from Dictionary.com LLC (2012). Dictionary. In Dictionary.com. Retrieved June 15, 2012, from Fisher, B. A. (2000). Techniques of crime scene investigation (6th ed., pp ). Boca Raton, FL: CRC Press. Freeman, S. (n.d.). HowStuffWorks "Learn how Everything Works!". "How Bloodstain Pattern Analysis Works". Retrieved 1998, from Gardner, R. M. (2005). Practical crime scene processing and investigation (1st ed., pp ). Boca Raton, Fla: CRC Press. Gutierezze, S. P. (1996, November). What The Blood Tells Us, by Sherry Gutierrez. Kenneth A. Rahn's Home Page. Retrieved July 3, 2012, from HemoSpat - Bloodstain Pattern Analysis Terminology - IABPA - Medium Velocity Impact Spatter (MVIS). (n.d.). HemoSpat - Bloodstain Pattern Analysis Software. Retrieved from Kuntz, S., Mutzel, E., Peschel, O., & Rothschild, M. (2010). Blood Stain Pattern Analysis. Forensic Science Medicine Pathology, 1(7), doi: /s Lee, H. C., Palmbach, T., & Miller, M. T. (2001). Henry Lee's crime scene handbook. San Diego, Calif: Academic. Lyle, D. P. (2004). Forensics for dummies (1st ed., pp ). Hoboken, N.J: Wiley. Nickell, J., & Fischer, J. F. (1999). Crime science: Methods of forensic detection (pp ). Lexington, Kentucky: University Press of Kentucky. Saferstein, R. (2001). Criminalistics: An introduction to forensic science (7th ed., pp ). Upper Saddle River, N.J: Prentice Hall. Spitz, W. U., & Fisher, R. S. (2006). Spitz and Fisher's medico legal investigation of death: Guidelines for the application of pathology to crime investigation (4th ed.). Springfield, Ill: Charles C. Thomas. Winterich, D. R. (2009). Bloodstain Patterns through Roadmapping. Forensic Magazine, 6(5), Retrieved from