the crime scene
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The Crime Scene. Chapter 2. Processing. Physical Evidence - encompasses any and all objects that can establish that a crime has been committed or can provide a link between a crime and its victim or a crime and its perpetrator. - PowerPoint PPT PresentationTRANSCRIPT
The Crime Scene
Chapter 2
Processing
• Physical Evidence - encompasses any and all objects that can establish that a crime has been committed or can provide a link between a crime and its victim or a crime and its perpetrator.
• Physical evidence can achieve its optimum value in criminal investigations only when its collection is performed with a selectivity governed by the collector’s thorough knowledge of the crime laboratory’s techniques, capabilities and limitations.
• Not every object at a crime scene is evidence
• Investigator must be able to recognize what could be potential evidence and must have it properly collected and preserved.
• Scientific analyses cannot overcome faulty criminal investigations.
• Evidence collection is not difficult and can be performed by anyone properly trained.
• Most police agencies have delegated the task of evidence collection to a specailized team of technicians.
Secure and Isolate
• First Responder - must take steps to protect and preserve the area to the greatest extent possible.
• First priority is given to providing medical assistance and arresting the perpetrator.
• Extensive efforts must be made to exclude all unauthorized personnel from the scene.
Lead Investigator• Must evaluate the area and determine the
boundaries for the crime scene.
• The path the perpetrator took to enter and exit is then determined.
• Obvious crime scene evidence must be documented and photographed.
• The investigator then performs an initial walk-through to gain an overall perspective and then develops a strategy for the systematic examination and documentation of the entire crime scene.
Recording• Cannot lose opportunity to work a scene in
its untouched state.
• Records will prove useful for further investigations and are required for presentation in court.
• Photography - unaltered condition
• Sketches - rough and finished
• Notes - detailed written description of scene
Photography• Objects should not be moved prior to being
photographed from all necessary angles.
• Medical necessity may required objects to be move before the pictures. This should be noted.
• Items that have been removed from the scene must NEVER be brought back into the scene to be photographed.
• Areas to be photographed include the crime location and all adjacent areas where important acts occurred immediately before or after the commission of the crime.
• All photographs should be taken from various angles.
• Photos must show location and orientation of the body; after body is removed photos of the floor under the body must be taken.
• Close-up photos showing injuries and weapons lying near the body must be taken.
• Photos are taken of physical evidence as it is found to indicate position and location relative to the entire scene.
• Close-up photos are also taken to record details of the object itself.
• Rulers or scales may be placed near the evidence and included in the photograph as a point of reference.
• Digital photography allows for a 3D image to be produced.
Sketches• After photographs are finished the investigator
will make a rough sketch of the scene.
• Rough sketch contains an accurate depiction of the dimensions of the scene and showing the location of all objects having a bearing on the case.
• Finished sketch is drawn with care and concern for aesthetic appearance.
Rough Sketch• Shows all items recovered as evidence as well as
other important features of the scene with a number or letter designation.
• Objects located by accurately measuring from two fixed points such as walls or corners.
• A legend listing all items items is placed below the sketch.
• The sketch must also show a compass heading designating north.
Finished Sketch
• Usually prepared with assisted technology.
• Drawn to scale.
• Must include information contained in the rough sketch to be admissible in court.
• Computer software has enabled this sketch to be as intricate as possible including the use of symbols to represent minute details.
Notes
• Note taking must be a constant activity throughout the processing of the crime scene.
• These must include detailed written descriptions of the scene with the location of physical evidence recovered.