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.