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THE CRIME SCENE. Physical Evidence Goals – Define physical evidence – Discuss responsibilities of the first police officer on the scene – Explain the.

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Presentation on theme: "THE CRIME SCENE. Physical Evidence Goals – Define physical evidence – Discuss responsibilities of the first police officer on the scene – Explain the."— Presentation transcript:

1 THE CRIME SCENE

2 Physical Evidence Goals – Define physical evidence – Discuss responsibilities of the first police officer on the scene – Explain the steps taken for thoroughly recording the crime scene

3 Physical Evidence As automobiles run on gasoline, crime laboratories “run” on physical evidence. Physical evidence encompasses any and all objects that can establish that a crime has been committed or can link a crime and its victim or its perpetrator – Examples- Hair, skin, fibers, fingerprints, blood, DNA, weapons, soil, glass, documents, etc.

4 Crime Scene Investigation Forensic science is an important element of the total investigative process but is only one aspect, crime labs do NOT solve crimes. If the investigator cannot recognize physical evidence or cannot properly preserve it for examination, no amount of sophisticated laboratory instrumentation or technical expertise can salvage the situation.

5 Crime Scene Investigation What needs to be done to avoid crime scene contamination? What are the issues that we would run into in investigating the scene?

6 The First Steps First priority should be given to obtaining medical attention for individuals in need of it and to arrest the perpetrator if he/she is there. As soon as it is possible, extensive efforts must be made to exclude all unauthorized personnel from the scene. – Do you think this would be an easy task? – Why is this important?

7 Step 1- Secure the Perimeter

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9 The first officer to arrive at the scene is responsible for securing the perimeter. – Make the scene large initially – Set boundaries – Look for footprints/ tire tracks – Physical evidence – Perpetrator entrance and exit route

10 Step 2- Record the Scene

11 Using your iPad, please visit the following website; – http://www.forensicmag.com/articles/2009/08/cri me-scene-photography-capturing-scene http://www.forensicmag.com/articles/2009/08/cri me-scene-photography-capturing-scene Read the article and answer the following questions- 1.) When should the crime scene photographer begin recording the scene? 2.) What should the photographer take photos of?

12 Step 2- Record the Scene Photography/video, sketches, and notes are the three methods for crime-scene recording. Ideally all three should be employed; however, as is often the case, personnel and monetary limitations may prohibit the utilization of photography at every crime site.

13 Photography/Video The most important prerequisite for photographing/taping a crime scene is for it to be in an unaltered condition. Unless there are injured parties involved, objects must not be moved until they have been photographed from all necessary angles.

14 Photography/Video Crime scenes should be photographed/taped as completely as possible – Area in which crime took place Distant, mid-range and close-up images “Four corners” of room/structure Points of entrance and exit – Bystanders – All adjacent areas – Body positions – Close ups of possible evidence Show their position and location relative the entire scene When the size of an item is of significance, a ruler may be inserted near the object and included in the photograph as a point of reference.

15 Sketches Once photographs are taken, the crime-scene investigator will sketch the scene. Rough Sketch —A draft representation of all essential information and dimensions at a crime scene. This sketch is drawn at the crime scene. It shows all recovered items of physical evidence Measurements Includes doors, windows and furniture

16 Rough Sketch

17 Sketches Finished Sketch —A precise rendering of the crime scene, usually drawn to scale. Unlike the rough sketch, the finished sketch is drawn with care and concern for aesthetic appearance. Many times your final sketch is completed with CAD

18 Finished Sketch

19 Notes Note taking must be a constant activity throughout the processing of the crime scene. These notes must include a detailed written description with the location of items of physical evidence recovered.

20 Notes They must identify: – The time an item of physical evidence was discovered. – By whom. – How and by whom it was packaged. – The disposition of the item after it was collected. Notes may be the only source of information for refreshing one’s memory. (Can be taped and later written)

21 Recording the Crime Scene Investigators have only a short amount of time to work a crime site in its untouched state. Every step of the investigation should be recorded thoroughly with an appropriate method. Such records will not only prove useful during the investigation but are also useful for presentation at a trial in order to document the condition of the crime site and to show the location of physical evidence.

22 JonBenet Ramsey Case Crime Scene Investigation- Please underline errors made in securing and processing the crime scene. Initially, the police conducted a cursory search of the house but did not find JonBenet. The house was not sealed off. Four friends along with the Ramsey pastor were let into the home and allowed to move about at will. John was permitted to leave the premises unattended for an hour and a half. Once hour after his return, John and two of his friends searched the house again. This time John went down into the basement where he discovered JonBenet’s body. He carried her upstairs, placing the body on the living room floor.

23 Crime Scene Investigation- Please underline errors made in securing and processing the crime scene.


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