Unformatted text preview: Charlie Zoller Criminalistics I : Crime Scene Midterm 11/15/12 1. List and describe 3 methods of crime scene sketching discussed in class. Which of these is best suited for interior, exterior, and remote crime scenes? Include a scenario where each method should be utilized. The 3 methods of crime scene sketching we discussed in class are Rectangular coordinates, triangulation, and baseline coordinates. Each of these methods can be suited for interior, exterior, and remote crime scenes. The first of the 3 methods, Rectangular coordinates; all the measurements are taken from the evidence to nearby walls or surfaces, also Measurements are all taken at right angles. This method is considered to be very fast and effective and easily understood by most. This method is most likely best suited for interior crime scenes. One scenario where rectangular coordinates would be used is if a man was shot in a square surrounding and crime scene investigators need information of how he was killed. The second method is called Triangulation. In Triangulation Measurements are taken from the evidence to specific points, and angular measurements meet to form a triangle. Triangulation can be used indoors or outdoors, and it may be more precise than Rectangular Coordinates, but can also be more confusing. Triangulation is best suited for interior crime scenes. Triangulation can be used if there is a scenario in which someone is called in an apartment and investigators need to find out how he or she did it using obscure angles. The third method is called Baseline Coordinates. In this method the Datum Point located is set by triangulation to landmarks, and GPS coordinates are also used. In addition the line is extended along a cardinal direction North, South, East, or West to measure evidence at right angles from line measurements from the baseline direction added. This method is best suited for exterior scenes with limited identifiable landmarks. This method is used if there is a scenario where investigators find a body in the ground. Charlie Zoller Criminalistics I : Crime Scene Midterm 11/15/12 2. Potentially, the crime scene provides a wealth of information. List and describe the six categories of “Information gained from the crime scene. There are six categories of “Information obtained from a crime scene.” The six categories are Corpus Delicti(1), Modus Operandi(2), the linkage of people, scenes, and objects(3), identification of suspects and substances(4), reconstruction of a crime(5), and proving the investigating leads(6). Corpus Delicti in literal terms is the body of a crime scene. It includes all the essential factors a crime scene has to offer. The second category is Modus Operandi. This is the mode of operation. It is the preferred method of operation by the criminal. This often has to do with serial offenders in such cases like rape, burglaries, and homicides. The third category is Linkage of persons, scenes, and objects. This refers to repeating modes of operation, and the relation of physical evidence to the crime scene such as a blood trace. The fourth category is the Identification of Suspects and Substances. This includes fingerprints, DNA, trace evidence and chemical analysis. The fifth category is the Reconstruction of a Crime. It is the final step in physical crime scene investigation. It means demonstrating how the crime was committed; recreating a likely scenario of what happened. And lastly Providing Investigative Leads, this means using the physical evidence obtained to provide useful information to an investigator. It includes traces, fingerprints and shoeprints usually. Charlie Zoller Criminalistics I : Crime Scene Midterm 11/15/12 3. Describe the purpose of both crime scene photographs and sketches and discuss how these two essential sources of documentation compliment one another. Crime scene photographs and crime scene sketches both compliment one another very well. The each serve a great purpose in Crime scene investigation. The purpose of Crime scene photography is intended to lead the investigator through the crime scene, and to document the scene before the investigators get to use it and move everything around. It is supposed to tell the character, and violence of the scene and show what type of residence it was. Crime scene sketches intend to provide an accurate record of the scene as one found it. It is created to be referenced by investigators, prosecutors, and other litigants, but predominantly intended for judges and people of the jury. Crime scene photographs and crime scene sketches compliment one another very well because an investigator can make a sketch the use it on Microsoft PowerPoint, 3d EyeWitness, Visio Professional or Cad zone. Then later use the two to compare to each other the angles and how a criminal went about committing the crime. Charlie Zoller Criminalistics I : Crime Scene Midterm 11/15/12 4. How should the three basic levels of crime scene photographs (Overall, Intermediate, and close- up) be taken and what is the purpose of each level. There are 3 different basic levels of crime scene photography. The 3 types are Overall, Intermediate, and Close Up. Each of the 3 serve a different purpose in trying to fully document crime scene photography. The first of the 3
is overall. The overall pictures are taken from all angles of the scene and intend to overlap one another. These overall pictures should depict the scene as it was found with no scales or markers added in; the “virgin scene.” The next of the 3 is Intermediate. The purpose of Intermediate pictures are to show the surroundings, but generally get closer to the object in the crime scene. Intermediate pictures are taken somewhat closer to the scene of the crime, but not as close as the last type of picture; Close- up. Close- up pictures are taken about a foot away from the crime scene objects. The purpose of these pictures are to go into defined detail, and show a genuine picture of the crime scene object. Charlie Zoller Criminalistics I: Crime Scene Midterm 11/15/12 5. Two basic formulas were discussed in regards to trajectory analysis. List each formula and explain how it should be applied to a reconstruction. (If you find it necessary to draw a diagram to help explain your answer feel free.) Two basic formulas for trajectory analysis are used for the reconstruction of a crime scene. These two formulas are the Horizontal Distance Formula, and Balthazard’s Formula. The first formula; Horizontal Distance helps to determine If the gun was held at a specific height, and what would be the horizontal distance be from the hole. In a scenario where a man got in trouble with the law because he was caught shooting at someone driving a car. This formula helps to see if a suspect is lying when he says he was far away from the car he was shooting at. When one can use the formula to see how close he was from the car. Major Height – Minor Height Horizontal Distance (HD) = Tangent of angle adjacent to HD The next basic formula is Balthazard’s formula. This formula helps one figure out the trajectory of the bullet holes. It shows what angle a bullet enters and object. For example one can figure out if a bullet entered and object at 90 Degrees, 45 Degrees, and 20 Degrees. 90 Degrees 45 Degrees Impact angle = Inverse Sine of Width of Hole Length of Hole 20 Degrees ...
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