Go to the following link: to answer the questions and help you solve the case.

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1 Name Date Go to the following link: to answer the questions and help you solve the case. Bloodstain Pattern Analysis: The examination of the, and of bloodstains in order to provide an interpretation of the physical events by which they were created that is based on the premise that all bloodstains and bloodstain patterns are characteristic of the that have created them. The interpretation of bloodstain patterns found at the scene or on exhibits such as the clothing of the principles of the occurrence can be used to: Confirm or refute concerning events and their sequence: (standing, sitting, laying) (blood smears, flow patterns and drip trails) Confirm or refute made by the principles in the case: Are the stain patterns on a suspect's clothing consistent with his reported action? Are the stain patterns on a victim and/or at the scene consistent with accounts given by the witnesses, victim or the suspect? Properties of Blood: Blood Volume On average accounts for % of total body weight to liters of blood for males to liters of blood for females A % blood volume loss, internally and/or externally is required to produce irreversible shock (death) A blood loss of internally/externally is required to cause incapacitation. Surface Tension in Blood: The property of the surface of the liquid caused by the forces of attraction between the molecules of the liquid that makes it and assume the smallest possible shape i.e. a blood droplet in flight will possess the shape of a (ball).

2 Target Surface Texture: Bloodstains can occur on a variety of such as carpet wood, tile wallpaper, clothing and the list goes on... The type of surface that a blood droplet strikes affects the amount of and (secondary) blood spatter. Blood droplets that strike a, like glass, will have or distortion on their peripheral edges. Blood droplets that strike will take-on a slightly different appearance and may tend to have " " on their peripheral edge. Surfaces such as or will be distorted to a much extent, sometimes producing satellite (secondary) blood spatter droplets and stains. General Categories of Bloodstains: Label each picture!

3 Directionality of Bloodstains: When a droplet ( ) impacts a surface at a perpendicular angle ( degrees) the resulting bloodstain will appear i.e. the length a width of the stain are _. When a blood droplet impacts a surface at an angle less that 90 degrees, the resulting bloodstain with have an or _ appearance. In addition, the tail of the droplet will indicate the direction of travel of the droplet when it contacted the surface i.e the opposite direction from where the droplet originated from. Area of Convergence and Area of Origin Determination: The common of can be determined based upon the geometric appearance of the bloodstains within a blood spatter pattern

4 The line drawn through the of each individual bloodstain can then be extended back to common. By calculating the each individual bloodstain, a 3- dimensional can then be determined mathematically or physically using strings. TRY IT! Measure the width and length of each bloodstain. Calculate the angle of impact (i) using your Calculator. Make sure you do not include any tails or satellite stains in your measurements. Angle of impact = ArcSIN of W/L ratio a) First calculate ratio (W/L) b) You should remember that you can use SIN -1 (2 nd key) to get degree of AOI

5 ANALYZE A CASE Test your Skills as a Bloodstain Pattern Analyst! As a bloodstain pattern analyst you have been called to the following scene by the police investigator. The police were called to the following scene when the apartment caretaker found the following blood patterns in the building and within suite 203. The resident in suite 203 cannot be located and it is not known who the victim is or what the person's injuries might be. You are asked by the investigating officer: Can you tell me what happened? Where was the victim initially attacked? What was the victim's position during the attack? What type of force created the bloodstains? Where/what do you think his injuries might be? This is an actual case and circumstances! Use the diagrams provided and answer the following questions! 1. The first photograph is going up to the second floor from the apartment entrance foyer. You then turn right and pass the next photo. Type of Blood Pattern: Blood from victim or assailant? Was person going up or down the stairs?

6 2. You continue up the stairs and enter into the second floor hallway at the door marked "Exit". You then turn to the right and walk towards suite 203, passing bloodstains on the door and frame to suite 201. You then make a left turn to suite 203. There are bloodstains on the wall across from the entrance door to suite 203. Type of Pattern(s): Victim or Assailant Blood? Where is victim s position? 3. You then enter suite 203 and observe bloodstains on the back of the door, on the wall to the left of the door, above the stove and on the upper bedroom door frame. These are the bloodstains on the wall, left of the door. These are the bloodstains above the stove around the bedroom door entrance.

7 Type of Pattern(s): Do you think this is the primary or secondary scene? What is a possible explanation of what may have happened here? Describe the weapon possibly used, number of people you believe were at the scene, location of initial attack, type of force, and possible injuries.