Introduction to forensics


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Year 10 Forensic Science
Introduction lesson

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Introduction to forensics

  1. 1. Year 10 Forensic Science What is Forensic Science? Hazards and Protection Collecting Evidence
  2. 2. Learning intention/goals To understand what Forensic Science is To understand the roles of Forensic Scientists To understand the hazards and risks associated with Forensic Science To become familiar with the integrity of collecting evidence Success criteria I understand what Forensic Science is I understand the roles of Forensic Scientists I understand the hazards and risks associated with Forensic Science I am familiar with the integrity of collecting evidence
  3. 3. WHAT IS FORENSIC SCIENCE? •the application of a science to answer questions of interest to a crime. •comes from the Latin forensis, meaning "of or before the forum." •In Roman times, a criminal charge would be presented before the public in the forum. Both the person accused and the accuser would give speeches. The individual with the best argument would determine the outcome of the case
  4. 4. •aka “The French Sherlock Holmes” •formulated the basic principles of forensic science •“Every contact leaves a trace” •Started the first police laboratory in Lyon in 1910 Edmond Locard (1877 – 1966)
  5. 5. Research ~ Hazards In pairs or using your BYOD, complete the following. You have 2 mins on the timer 1. What do these initials mean: • HSE • PPE • COSHH 2. Complete the following: – A hazard is – A risk is 3. What is meant by sharps? Health and Safety Executive Personal Protection equipment Control of Substances Hazardous to Health Anything that might cause harm. The chance that someone could be harmed. Any sharp instrument or object.
  6. 6. Method of entry into the body inhalation skin absorption ingestion injection Nature of hazard contaminants that make contact with the skin contaminants such as sharp objects that can puncture the skin airborne e.g. dusts, smoke, vapours, gases contaminants that are able to enter the mouth Action to reduce the risk wash hands before eating or smoking. Do not bring food into unsuitable areas. Use equipment such as safety glasses, gloves and other protective clothing Exercise caution when handling. Wear gloves at all times. Dispose of sharp objects in special containers. Ventilation and/or respiratory protection masks.
  7. 7. Protective clothing Face mask Protects against inhaled particles and prevents contamination from the officer’s saliva. Goggles Protect eyes from chemical hazards. Hooded Plastic Suit Protects the officer at the scene and prevents contamination of the scene. Gloves Protect from materials absorbed through the skin, prevents contamination by fingerprints and DNA. Shoe covers Prevent footprints from damaging evidence. Complete the task in your booklet on protective clothing.
  8. 8. Roles Detective (D) Senior Investigating Officer (SIO) Scenes of Crime Officer (SOCO) Senior Scenes of Crime Officer (SSOCO) Scene Guard To question suspects and investigate lines of enquiries. To co-ordinate the overall investigation To record and recover valid evidence at crime scene . To manage the forensic examination of the scene. (SG) To preserve the scene and to make sure no unauthorised persons enter the scene.
  9. 9. Risk Assessment What hazards might be present here? What could you do ensure risk is minimised?
  10. 10. Processing a Crime Scene Valid Evidence Valid evidence is based on the truth. It can be accepted in court. Forensic scientists use two procedures to make sure evidence is valid: • Avoid contamination •Record accurately
  11. 11. Contamination Definition: The unwanted transfer of material which must be avoided at a crime scene Individuals can contaminate the scene or evidence at any time by: • Leaving fingerprints / hairs / fibres / DNA • Not sealing the evidence properly • Putting more than one piece of evidence in a bag at once • Using old equipment Contaminated evidence can not be used in a court of law and may result in criminals being set free.
  12. 12. Establishing Evidence You will need to find out: • How contamination of the crime scene is prevented • How the officers protect themselves from harm • What photos and measurement were taken • What evidence is collected, and how it is stored. • What can be learned from the evidence? Protecting the evidence at the Crime scene Look at the next slides and determine the measures that have been put in place to protect the validity of the evidence.
  13. 13. Picture A ~ Cars Tape used to created a cordoned off area to prevent people from entering the scene unauthorised. Police officers used to prevent unauthorised people entering the area.
  14. 14. Picture B ~ Scene of Crime Officer (SOCO) at work Tent Provides screen and distinct barrier Suits SOCOs gathering evidence correctly dressed. NB. Any Police Detective entering the scene would be required to wear a protective suit. BUT they don’t on TV do they? Stepping Plates Provide a safe and secure way of approaching the scene.
  15. 15. Picture C ~ On the ground and around Tent Provides screen and distinct barrier Crime Scene Tape Creates an inner cordon. Full protective clothing! Evidence markers.
  16. 16. Processing a Crime Scene Correct processing of a crime scene is essential to gather as much information as possible and prevent contamination. STEP 1 INTERVIEW - The SOCO arrives on the scene and makes sure it is secure. An initial walk-through is conducted to get a feel for the crime scene. The first officer at the scene and/or the victim is interviewed to ascertain the "theory" of the case; what allegedly happened, what crime took place, how was the crime committed etc. This information may not be 100% factual but it will give the SOCO a place to start from. The SOCO also needs to find out if anything has been moved. Potential evidence is noted but at this point, nothing is touched.
  17. 17. Processing a Crime Scene STEP 2 DOCUMENTATION – Is the "theory" of the case supported by what the SOCO observes? Examine the scene to identify evidence, point of entry and exit, the general layout, etc. The SOCO thoroughly documents the scene as well as any potential evidence by taking photographs and drawing sketches during a second walk-through. Sometimes, a video walk-through may be conducted. Again, nothing is touched.
  18. 18. Processing a Crime Scene STEP 3 PROCESSING - Now it's time to touch stuff -- very, very carefully. The SOCO systematically collects all potential evidence, tagging it, logging it and packaging it so it remains intact for further analysis by a crime laboratory. The lab processes all of the evidence collected at the crime scene. When the lab results are in, they go to the lead detective on the case.
  19. 19. It is essential that any items of physical evidence can be traced from the: crime scene → lab → lab report → courtroom This is known as maintaining the chain of custody or continuity of evidence. If the chain is broken, the forensic investigation may be fatally compromised. Processing a Crime Scene
  20. 20. Search Patterns There are several search patterns available for a SOCO to choose from to assure complete coverage and the most efficient use of resources.
  21. 21. Search Patterns 1) Inner Spiral The SOCO starts at the perimeter of the scene and works toward the centre. 2) Outer Spiral The SOCO starts at the centre of scene (or at the body) and works outward. Spiral patterns are good if there is only one SOCO at the scene.
  22. 22. Search Patterns 3) Parallel The SOCO team form a line and walk in a straight line, at the same speed, from one end of crime scene to the other. 4) Grid Two parallel searches, offset by 90 degrees, performed one after the other.
  23. 23. Search Patterns 5) Zone The lead SOCO divides the crime scene into sectors, and each team member takes one sector. Team members may then switch sectors and search again to ensure complete coverage.
  24. 24. TASK Read the Allison Bayden –Clay murder case and decide which search patterns were employed to gather evidence and why. • Quadrant search (Zone) • Link Method • Strip or line search (Parallel) • Grid • Spiral Search (inner and outer) You will need to include a diagram of the SOCOs pathway through the crime scene. Also include any advantages and disadvantages of the search patterns. In your opinion, which would be the most ideal search pattern?
  25. 25. Trace evidence (gunshot residue, paint residue, broken glass, unknown chemicals, drugs, poison) Impressions (fingerprints, footprints, tool marks) Body fluids (blood, semen, saliva, vomit) Hair and fibres Soil and insects Weapons and firearms evidence (knives, guns, bullet holes, cartridge casings) Documents (diaries, suicide note, phone books; also includes electronic documents like answering machines, text messages) In General:- What kind of evidence might a SOCO be searching for?
  26. 26. Video: Forensic Science used to solve real crime scenes • GT2M&list=PL89QP7ZwONKmVLlYwPyf6aI- wIrQjbnqX
  27. 27. Review: In your Booklets • Name 3 different occupations related to Forensic Science and briefly describe their role .......................................................... • Valid evidence is dependent upon two things. Name them ............ • Forensic Science is the ..............................