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Crime Scene Procedures

Crime Scene Procedures. Introduction. Derek Walker 4 th year Forensic Science Student University of Ontario Institute of Technology (UOIT) Bachelor of Science ( Hons ) Minors in Biology and Chemistry Research experience: Forensic P sychology (eyewitness identification) Microbiology

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Crime Scene Procedures

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  1. Crime Scene Procedures

  2. Introduction Derek Walker • 4th year Forensic Science Student • University of Ontario Institute of Technology (UOIT) • Bachelor of Science (Hons) • Minors in Biology and Chemistry • Research experience: • Forensic Psychology (eyewitness identification) • Microbiology • CCSS graduate

  3. What is Forensic Science? • Forensic: “pertaining to legal matters” • Science: “the systematic organization of knowledge through the experimental testing of hypotheses for the purpose of explaining phenomena in our universe” • Essentially, “The Scientific Method” • Forensic Science: “The application of the Scientific Method to legal matters” • Forensic Science encompasses a wide variety of disciplines

  4. Disciplines of Forensic Science

  5. Personnel Involved in Investigations of Crime • First responders • Crime scene investigators • Forensic Identification Officer • Scene of Crime Officer (SOCO) • Forensic Scientists • Typically experts in a specific discipline • Coroner (Medical Examiner) • In Ontario, all are physicians • Forensic Pathologist

  6. Some scenes require experts to collect evidence or provide analysis Homicide Investigations Coordination of crime scene investigation If death appears suspicious Forensic Identification Officer Forensic Scientists SOCO First Responders Many police services don’t have the resources to analyze all types of evidence, so it is outsourced Police officers, EMS, firefighters Homicide Crime Labs, other external agencies Determines manner of death, issues death certificates, recommends how to prevent similar deaths Body goes to autopsy after being documented Coroner and pathologist communicate to report cause and manner of death Forensic Pathologist Coroner

  7. Other Types of Investigations • Office of the Fire Marshal • Investigate major fire scenes • Special Investigations Unit • Investigate scenes where police have caused serious injury • Ministry of Labour • Investigate industrial and farming deaths

  8. Crime Scene Investigation Misconceptions Clip from Superbad

  9. Crime Scene Investigation Misconceptions – The CSI Factor • Don’t drive hummers • Don’t wear Prada to crime scenes • Don’t wear high heels to crime scenes • Don’t utter cheesy one-liners like Horatio at the start of every investigation • Don’t find fingerprint or DNA matches in minutes • Don’t investigate in the dark

  10. Crime Scene Management • Preserves the integrity of evidence to ensure that it is admissible in court • Initial response: • Preservation of life if possible • Isolate suspects and witnesses • Protect the scene • Record scene details • i.e. time, date, personnel and persons present

  11. Initial Response • First priority is always to assist a victim who is still alive • Limit access to scene • Be aware of possible evidence

  12. Scene Protection Video http://www.youtube.com/watch?v=5LbV9l9d2Cw

  13. Scene Protection • Establish a perimeter that appears to encompass scene in its entirety • Block off boundaries • Physical presence of police and crime scene tape • Remove unnecessary personnel • Chose a “path of contamination” and avoid walking around aimlessly

  14. Scene Continuity • Locard’s Exchange Principle:“Every contact leaves a trace” • Must ensure not to deposit foreign objects, or take away any objects from the crime scene • Starts with personal protective equipment (PPE)

  15. PPE

  16. Investigative Teams • Crime scene investigation is a team effort • Searching usually requires at least 2 people, but can be a lot more if the scene is bigger • 2-3 people for photography • 2-3 people for sketches and measurements • 2-3 people for collection of evidence • 1 person to take notes

  17. Scene Examination • Durham Regional Police Services Forensic Identification Unit uses LOSER principle • Listen to victims/witnesses • Observe the scene • Search victims and scene for evidence • Evaluate if evidence adds up to statements • Record the scene

  18. Scene Observation • Helps to choose a path which will prevent any unnecessary contamination • Allows you to see where the body is located within the scene • Can give a general idea of where to look for evidence • Allows you to judge which type of search method is best for the scene

  19. Scene Search • Should be done in a systematic and controlled manner • Begin with an initial walkthrough • Note location of evidence so that you can return to collect it later • Method of scene search will depend on number of CSI’s and size/type of scene

  20. Search Methods • There are 4 general types of searches: • Spiral • Strip • Grid • Zone • Some methods are more effective for different types of scenes

  21. Spiral Search • Start in the middle of an area, and spiral outward/inward in a clockwise/counterclockwise direction • Effective in small interior rooms

  22. Strip Search • CSI’s begin at one end of search area standing directly beside each other, and walk (or crawl) toward the opposite end of the search area • Advantageous for large outdoor scenes

  23. Grid Search • CSI’s begin at one end of search area, and proceed to other end in a straight line • Done once again except same area is searched perpendicularly to initial search direction • Advantageous because the same area is searched twice

  24. Zone Search • Search area broken down into zones, and each zone is searched separately • Useful in small confined spaces

  25. Types of Evidence • Common types of evidence: • Fingerprints • Footwear impressions • Firearms, weapons and toolmarks • Trace evidence • Biological evidence

  26. Search Tools • Oblique lighting • Angled light that causes shadows of trace evidence to become more visible • Chemical reagents • Phenolphthalein (Kastle-Meyer test) • Luminol • Polilight • Different wavelengths of light can cause certain invisible biological specimens to fluoresce

  27. Polilight

  28. Polilight Video http://www.youtube.com/watch?v=QoyRenZMldE&feature=related

  29. Luminol • Reacts with oxidizing iron present in hemoglobin to produce a strong blue chemiluminescene • Can detect trace amounts of blood that may not be visible to naked eye • Can show if there is evidence of an attempted clean up • Doesn’t react specifically with blood

  30. Luminol Video http://www.youtube.com/watch?v=J6Lr83Jgp_I&feature=results_main&playnext=1&list=PLC8565883057111BC

  31. Luminol

  32. Phenolphthalein • Indicator used in Kastle-Meyer test as a presumptive test for blood • Reacts with hemoglobin which has peroxidase-like activity • Can detect very small amounts of blood • Can react with natural produced vegetable peroxidases • Found in broccoli, cauliflower, horseradish

  33. Scene Documentation • Most important part of investigation • When case eventually goes to court, must be able to account for all evidence, its exact location in the scene, and who has been involved in the investigation • Different types of scene documentation: • Photography • Measurements • Evidence • General notes and logs • Sketches

  34. Crime Scene Photography • Evidence and scene are photographed as it is found • Provides accurate visual descriptions for future analysis by investigators, attorneys, judges/juries • Shows that evidence hasn’t been altered or tampered with between collection, and as an exhibit in court • Gives context of scene, and shows areas of interest • Take overall, mid-range, and close-up photographs

  35. Crime Scene Photography • Overall shots • Intend to show as much of scene or area of interest as possible • Mid-range shots • Focus on an area of interest • Includes objects that are also found in overall shots • Used to establish location of close-ups • Close-up shots • Taken using macro lens • Show detail of evidence • Take shots with and without scale • Film plane must be perpendicular to object

  36. Crime Scene Measurements • Used to visualize the exact position of evidence/objects in the scene • Also to visualize where windows, doors and points of entry are located in relation to evidence/objects • Allows reconstruction of scene at a later date • Measurements must be very precise • Made with tape-measures, rulers, laser, etc. • Movable objects measured to points of reference • Usually immovable objects or landmarks

  37. Evidence Collection • Depends on type of evidence being collected • Packaged in a manner that ensures continuity of evidence • Some evidence can be damaged by the method of packaging • Most fragile or weather dependent evidence collected first • Chain of Custody is started upon collection

  38. Notes and Logs • Meticulous notes are key to any investigation • Forces investigators to commit observations to writing • Corroborates statements • Refreshes memory • Detailed narration of all actions taken at the crime scene in chronological order

  39. Notes and Logs • What to include in notes: • Date and time • Location of scene • Description of scene and surrounding area • Who requested investigation • Names of officers, investigators, emergency personnel, witnesses, suspects, detainees • Name of investigators associated with tasks they were responsible for (photographer, sketcher, etc.) • Weather, lighting conditions • Location and description of evidence, and who collected it

  40. Notes and Logs • Logs to catalogue all photographs, measurementsand evidence

  41. Crime Scene Sketches • Supplement reports and photographs • Photos don’t always depict exact location of objects or their relation to other objects • Photographs can sometimes be deceiving due to perspective or distortion • Excellent visual aid for juries in court • Two phases of sketches • Rough sketch • Finished/Formal sketch

  42. Crime Scene Sketches • Rough sketch • Done free-hand at scene • Never replaced by finished sketch and is considered evidence as well • Often compared to finished sketch in court

  43. Crime Scene Sketches • Finished sketch • Correct any mistakes in rough sketch • Presents clean, clear diagram of scene with scaled measurements included

  44. UOIT Crime Scene House

  45. UOIT Crime Scene House • Stage mock crimes and use forensic investigative methods to “solve” crimes • In 2nd year, learn basic investigative techniques • Dusting for fingerprints, taking toolmarkand footwear impression casts, collect biological evidence, collect trace evidence (paint, glass, powders) • In 3rd year, apply investigative techniques to full investigations such as a hit and run, a shooting case, a sexual assault, a homicide, and a suspicious death • Need to document really well, because one of these cases goes to mock court!

  46. UOIT Forensic Science Program • Strong base in Biology and Chemistry • Lots of lab work • Mini-research projects • Opportunity to do honours thesis project with internal or external supervisors

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