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.