Crime Scene Investigation

Transcription

1 Crime Scene Investigation

2 The 7 S s of Crime Scenes 1. Secure the scene 2. Separate witnesses 3. Scan the scene 4. See the scene 5. Sketch the scene 6. Search for evidence 7. Scene evidence collection

3 First Responding Officer 1 Preserve life 2 Secure Crime Scene

4 Police officers: respond & manage

5 Separate the Witnesses Avoid collusion

6 Detectives: Talk to witnesses & follow leads

7 Scan the scene

8 See the Scene Photographs/ Video

9 Sketch the scene

10 Search for evidence

11 District Attorney & Judge: warrants & law

12 4 th Amendment: protects against illegal search and seizure

13 Warrant 5 legal ways to search: Emergency circumstances Prevent immediate loss of evidence Person under arrest Consent

14 Scene evidence collection Crime scene investigators

15 Medical Examiners: Examine body *at scene *at morgue Determine *time of death *cause of death

16 Forensic Specialists: type depends on evidence entomologists (bugs), anthropologists (bones), psychologists, etc.

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19 1. Police Officers 2. Crime Scene Investigators 3. Medical Examiners 4. Detectives 5. Specialists

20 1. Police officers usually first to arrive at scene a. District attorney may be present determines if a search warrant is needed

21 2. Crime-scene investigators a. document crime scene in detail b. collect physical evidence c. include recorders write down data/info. sketchers draw/sketch scene photographers evidence collectors

22 3. Medical examiners also called coroners determine the time & cause of death

23 4. Detectives look for leads interview witnesses go over evidence with investigators

24 5. Specialists - consulted if required by the evidence entomologists (insect biologists) forensic scientists forensic psychologists forensic engineers forensic anthropologists

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26 Crime Scene Search

27 Consent to Search Consent must be given voluntarily. Consent can be withdrawn at any time. Burden of proof showing that consent was lawfully obtained is on the police. Evidence obtained in an unlawful search is inadmissible in court. If possible have a witness sign the consent to search.

28 Consent to Search (cont.) Written/Verbal consent by parties with proper standing Always get consent in writing. Verbal consent is allowed but difficult to uphold in court. Person giving consent must have the mental capacity to do so. Proper standing: persons who have legal control or a legal right to the dwelling or vehicle. Consent must be obtained from all parties present. Example: If a husband and wife are present, both must give consent

29 Objectives of a Crime Scene Search Determine whether or not a crime has been committed Locate specific physical evidence: Corroborate witness statements Explain what occurred. Support or reject proposed theories as to what occurred and how.

30 Search Patterns Point to Point Strip (line) Search Double Strip Search Quadrant Spiral Aerial

31 Point to Point Search Preliminary step in evaluating the scene Moves in order of appearance of evidence Advantage: quick scene evaluation Disadvantage: often disorganized

32 Most effective for large outdoor scenes Stakes or lines can be used to set up lanes Very thorough method Allows utilization of additional personnel Searchers can be alternated from strip to strip Strip (Line) Search

33 Strip search that takes place in two directions Ex: After searching from north to south, move from east to west Increases thoroughness of the search Double Strip Search

34 Quadrant/Sector Search Indoor or outdoor scenes with regular patterns or assigned borders Resembles a grid AKA room to room for indoor searches Permits different search patterns to be used in each sector if needed

35 Circular/Spiral Search Search proceeds in a circular motion. Can be effectively used by one officer. Useful when an item is missing from the center of a crime scene. May start at center of scene or on outer perimeter.

36 Aerial Search Search conducted by a fixed wing aircraft or helicopter Useful for large expanses of land or water

37 Rechecking an Area When evidence is not found Alternate search groups Alternate searchers within groups Utilize all of your resources Did you choose the correct search pattern? Did you include the entire crime scene area? When preparing to leave Always complete an exit search, looking for anything that might have been missed, including your own tools and equipment

38 When choosing a search pattern consider the following: Size of the area to be searched Number of personnel available for the search Specialized equipment needed Evaluation of possible hazards present Physical characteristics of the search area (size, vegetation density, indoor or outdoor scene, etc.) Size of object/ evidence being searched for Degree of thoroughness required ( most important factor)

39 Implementing the search Coordinated by one officer (lead investigator, supervisor, etc.) Determine a starting point If using multiple officers, establish headquarters outside the area to be searched Conduct a briefing session Establish speed at which the search will be conducted Maintain communications with searchers

40 Assessment What type of search should you use if your crime scene has 2 acres of land to cover?

41 Assessment What type of search should be used to search 20 acres of land?

42 What type of search would be best for this scene? Assessment

43 Assessment What must you do prior to executing a search? Give one objective of conducting a search.

44 Court Cases Mincey V State of Arizona, 1978 Thompson V Louisiana, 1984 Michigan V Tyler, 1978 Oliver V United States, 1984 Bumper V North Carolina, 1968

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46 Crime Scene Notes, Sketches & Diagramming

47 Purpose: Record scene Reconstruct scene Support testimony

48 Crime scene notes Detailed notes about scene: Description of scene

49 What do you notice?

50 KEY ideas: Measure Accurately! Show all parts of scene

51 Datum Point: permanent (immobile) reference point

52 Making a Sketch 1. Set boundaries 2. Rough sketch scene 3. Indicate North 4. Measure Boundaries 5. Measure objects 6. Assign objects numbers/letters for sketch key ( A = gun, B = bullet, C = blood )

53 Measurements:

54 Measurements:

55 Measurements: Triangulation

56 Measurements: Triangulation

57 If there s a body Measure from head, hands, feet, elbows, knees, chest, etc.

58 After Rough Sketch Create a final sketch Computer- Aided Drafting (CAD)

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61 CSI Photography

62 Photography

63 Crime scene photographs: 1) Show the layout of the crime scene 2) Show the position of evidence 3) Show the point of view of: Victim Suspect Witnesses 4) Show the condition of evidence

64 Crime Scene Photography Log Similar to an evidence log Information about each crime scene photograph Date and time the photograph was taken Location of the picture Camera settings (f-stop and shutter speed) Lighting used and lighting angle (if applicable) Brief description of the subject of the picture

65 Most important: DON T CHANGE ANYTHING! Visually walk jury through the scene

66 Long Range (Overall) Photos Shows area surrounding scene

67 Evidence Establishing Photos Shows layout of scene Shows position of evidence within scene

68 Close-Up (Detail) Photos Shows one piece of evidence in it s surroundings

69 Identification Quality Photos Used to identify piece of evidence use scale to show size

70 Special Crime Scene Photography Bloodstain photography Treated with luminol Photographed in complete darkness Latent fingerprint photography 1:1 scale Requires a special camera or an adapter. --Black and white film used to show greater contrast

71 How CSI Photography is done SLR cameras Expensive High-quality Lots of control

72 Aperture How much light is let in to the camera f-number small number = wide aperture = lots of light

73 Big aperture = lots of light (bright) Small aperture = not much light (dark)

74 Depth of Field How much area is in focus Small aperture = high f-number = big D.O.F. Bottom photo = large D.O.F.

75 Shutter Speed Length of time the aperture is open Fast speed = not a lot of light let in = darker, but less risk of blur Slow speed = lots of light let in = brighter, but more risk of blur

76 Camera Modes Macro = extreme close up Night = slow shutter speed Portrait = small D.O.F. Landscape = big D.O.F. Sport = fast shutter speed