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 Arriving at a “Crime Scene”—the location where an offense takes place is referred to as the crime scene.

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Presentation on theme: " Arriving at a “Crime Scene”—the location where an offense takes place is referred to as the crime scene."— Presentation transcript:


2  Arriving at a “Crime Scene”—the location where an offense takes place is referred to as the crime scene.

3  When officers arrive they have three tasks to perform:  Assist injured people/call an ambulance  Call in reinforcements to eliminate hazards (bombs, fires etc.)  Continue to search the crime scene—even if they think perpetrators have left. ASSUME PERPETRATORS ARE PRESENT AND ARMED.

4 Protecting and Preserving the Crime Scene—success in prosecuting a case often depends on the evidence collected. Officers must establish two boundaries— the centre (where the offense was committed) and the perimeter (surrounding areas where evidence may be present)

5  Crime scenes are preserved for three reasons: allow for search, seize and collect evidence and ensure evidence is not contaminated (loss, destruction or alteration of physical evidence)

6  Officers role at a crime scene—Four types of officers investigate at a crime:  Scenes of Crime Officer  Criminal Identification Officer  Criminal Investigations Bureau Officer  Patrol Officer

7  Scenes of Crime Officer—trained in evidence collection/preservation  Criminal Identification Officer— resp. for searching the crime scene for evidence

8  Criminal Investigations Bureau Officer—detective with experience in specific area (homicide, robbery, sexual offences)  Patrol Officer—usually first on the scene. Must secure crime scene/arrest suspects.

9  Collection, preservation and analysis of evidence is crucial  Physical evidence is defined as: any object, impression or body element that can be used to prove or disprove facts relating to an offense  Valuable because it often carried greater weight in court than witness statements

10  The use of biochemical and other scientific techniques to analyze evidence in a criminal investigation  Work done mostly in the lab but experts also testify in court  Examples: autopsy, firearms/ballistics, forensic chemists, etc

11  The tools used in the commission of a crime leave an imprint behind  May have individual characteristics  Most common: hammer, screwdriver, crowbar

12  Patterns or marks found on surfaces and caused by various objects  Fingers, gloves, shoes, tires, tools etc  Impression recorded by photographing/scanning it or taking a mould  Two characteristics: 1. Class characteristics: general attributes 2. Individual characteristics: specific to that object

13  Patterned marks left by a fingertip (also hands, feet, toes)  Unique and never change  Visible fingerprint: print formed in blood, grease or some other substance—seen by the naked eye  Latent fingerprint—formed by natural oils and perspiration. Invisible to the naked eye  Fingerprints can sometimes be left INSIDE gloves

14  Can be matched to suspect  Best if they have four prints—two of each foot  Can determine height, weight, injuries, whether the suspect was carrying anything, walking or running

15  Can determine the make of tire  make of car (sometimes)  the direction the car was travelling when it entered/left the crime scene

16  Crimes often result in the transfer of bodily fluids  Blood, semen, mucus, sputum, hair, skin  Sent for laboratory analysis  Analyzed for a match to the suspect  Hair and fibres may also be matched

17  Proper labelling is important  Who has contact with the evidence  The date and time the evidence was handled  The circumstances under which the evidence was handled  What changes, if any, were made to the evidence

18  Brief description  Police case number  Date collected  Location of collection  Brand name of item (if any)  Serial number  Name and badge number of officer who collected  Destination for storage or analysis

19 Fingerprinting Ballistics Impressions (imprints) Blood Tire/car tracks Autopsy Anthropology DNA Poisons Tool impressions Bodily Fluids Hair Analysis Forensic Dentistry Facial recognition software

20  Creativity.  Group Dynamics  Organization  Presentation Skills  Class mark  Activity  Case discussed Total -50 Students will have 5 days to complete the task.- Due on Tuesday 6th, November 2012.

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