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Crime Scene Procedures

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Presentation on theme: "Crime Scene Procedures"— Presentation transcript:

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
Physiological Social Sciences Criminalistics Digital Physical pathology psychology ballistics computers accident reconstruction anthropology psychiatry dactology databases physics entomology toxicology networks engineering biology document analysis mobile devices fire investigation chemistry video botany audio

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

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 Chemical reagents Polilight
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

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

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


34 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

35 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

36 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



39 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

40 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

41 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

42 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

43 Notes and Logs Logs to catalogue all photographs, measurements and evidence

44 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

45 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

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


48 UOIT Crime Scene House

49 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 toolmark and 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!

50 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

51 UOIT Forensic Science Program - Courses
1st year General courses: biology, chemistry, physics, calculus, computers, introduction to forensic science 2nd year Organic chemistry, cell biology, physiology, anatomy, genetics and molecular biology, biochemistry, statistics and probabilities, introductory psychology

52 UOIT Forensic Science Program - Courses
3rd year – forensic biology, forensic chemistry, analytical chemistry, instrumental analytical chemistry, physical chemistry, principles of pharmacology and toxicology 4th year – forensic drug chemistry and toxicology, interdisciplinary topics in forensic science, law for forensic scientists, forensic psychology, forensic physics* Plus electives

53 UOIT Forensic Science Program
Intimate classroom sizes Hands-on experience with instruments used in the field Prepared very well for work force Different types of research currently underway Decomposition chemistry, forensic entomology, forensic microbiology, computer-based blood spatter analysis

54 Questions? Or Laura Benninger – Forensic Science Program Director

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