lecture 11 searching the scene logic in action n.
Skip this Video
Loading SlideShow in 5 Seconds..
Lecture 11 Searching the Scene: Logic in Action PowerPoint Presentation
Download Presentation
Lecture 11 Searching the Scene: Logic in Action

Loading in 2 Seconds...

play fullscreen
1 / 53

Lecture 11 Searching the Scene: Logic in Action - PowerPoint PPT Presentation

Download Presentation
Lecture 11 Searching the Scene: Logic in Action
An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. Lecture 11Searching the Scene: Logic in Action Collecting evidence without a valid reason is also stupidity in action.

  2. Searching: A Philosophy • The crime scene • The place where individuals participated in an event at a • point in time that resulted in the creation of evidence • Finding this evidence that links the participants to the scene is • why crime scene investigations exist and why searching is critical. • Scene Type Examples • Hit and run cases: • Two cars - one hitting the other – one • leaves the scene. • A single car hitting a pedestrian and • leaving the scene. • Sexual battery case: • Assailant breaks into apartment or house • Assailant abducts the victim off the street. • Homicide cases: • Violent dispute between spouses, • A shooting in a drug case The crime might not define precisely the types of evidence present. BUT Scene scientist/investigators understand that certain crime types spawn specific types of evidence.

  3. Archiving and Searching Common Scene Types • Crime types … • Investigators need to understand the nuances of each. • Each crime scene is unique and each presents challenges different from the so-called norm • Different crime types present overlapping categories of evidence because, • What starts as a burglary may become a homicide or a sexual assault. • Specific attributes will occur more frequently with a particular crime type, • Semen in sexual assault cases. • The forensic archivist’s responsibility is to capture the scene photographically or by sketching which should ultimately lead to evidence, which is collected. • During the archiving process, the investigator who “finds” evidence should alert search team and team leader.

  4. Processing Or Investigation? • Scene investigation is NOT a blind endeavor • Scene investigations are extremely complex • Searching is crux of the investigation • Many believe searching the scene is a simple, thoughtless process that anyone can perform. • Certainly archiving is important, for if done badly, anyone examining the scene after the fact will not “see” the original scene. • Poor approach to searching leads to second guessing, • If search is conducted logically and systematically, it will be comprehensive and result in success • Police agencies often call it “processing the scene. • The term screams simplicity • Exercise requiring minimal thought to what is being done or why. • Definition of investigation is more rigorous and appropriate. “Processing” should be replaced with something that projects cognizant thought, such as investigation.

  5. Processing Or Investigation? “Processing the scene,” Modern texts lull students, novice investigators and seasoned investigators into believing that scene searching is a simple process. Process: “a series of actions or operations conducing to an end; especially : a continuous operation or treatment especially in manufacture” Processing is mindless activity and simplicity in action. The term should be replaced with something that projects cognizant thought, Investigation; “Transitive verb: to observe or study by close examination and systematic inquiry. “Intransitive verb: to make a systematic examination; especially : to conduct an official inquiry.” Scene investigation and searching is more than a “process.” It is a scientific endeavor and investigation, and certainly more than a simple "process."

  6. What is the Scene Search? • Three components • The Intellectual aspect– • The Crime Scene Investigative Cascade • The logic to devise a strategy for the search • On-scene activities. • Byproduct of two activities: • Original walk through with the first officer • Archiving.

  7. Why the Walk-Through? • An aspect of scene management • Team leader observes and absorbs the macroscene elements during the walk-through • Gathers information about the scope, size, and location of obvious evidence • Devises an initial search strategy • Recognizes immediate fragile evidence • Need to protect this evidence

  8. Why Archiving? • Archiving gives the only pictorial perspective • Illustrates how macroscene elements relate to each other. • Shows the relative location of evidence • Its interrelatedness becomes obvious. • As such it shows the location and relatedness of obvious macroscene evidence • If the archivists and team leader are in synch, information emerges from the chaos that is the hallmark of all crime scenes.

  9. What About Searching? The Scene Search Logic in Action The Meat and Potatoes • An integral arm of scene management and archiving. • The team leader and the team design search strategy based on logic • Not on a "method" published in a text book. • Proper search requires understanding of the scene. • Mental and physical activities are inextricably joined, • If scene management is the glue that holds the investigation together, • Scene search is the meat and potatoes of the investigation. Scene Management The Investigative Glue Archiving (Video/Photo/Sketch) Eye for the Future

  10. Defining the Search

  11. Defining the Search • Assume investigative team has legal right to investigate • If so, then the crime scene search begins when the team leader walks through the scene for the first time with the first or responding officer. • Team leader “sizes up” or takes inventory of the scene and assimilates first impressions. • Initial investigative strategy and precautions take shape, • Macroscene elements and other scene nuances absorbed.

  12. Immediate Concerns

  13. Modern Considerations • Modern crime scene investigation texts consider the scene search as a methodical process and often presented as a “method.” • They promulgate “named” procedures designed for specific crime scene types, such as for indoor and/or outdoor scenes. Such a simplistic approach is ridiculous. • Intent of “methods” is not to convey simplicity • Present inexperienced and experienced investigators a roadmap so they can avoid making serious mistakes, such as missing important evidence. • Minimizing errors is better accomplished in another way.

  14. Successful Searches General Guidelines

  15. Effective Management • Minus a strong, experienced manger, scene searches and the entire investigation will be chaotic and doomed to fail. • A strong leader keeps team focused, • Assigns roles when required and • Keeps the investigation on track. • Novice investigators and some seasoned investigators tend toward random searches without rhyme or reason except to “follow their nose.” • Effectively managed teams are efficient and thorough.

  16. Indoor Crime Scenes • Each scene is different. Homicides in large cities often occur in apartments…. Seemingly similar circumstances … they are not. • Different geography, clutter, etc. • Some might be air conditioned and comfortable in the summer • Others may stiflingly hot, sticky and uncomfortable. • Differences in temperature and humidity make can dramatically affect the success and efficiency of the investigation. • A scene in the middle of July when the temperature is 97oF and the humidity 92%, unpleasant odors, such as coming from a decomposing body, can be oppressive. • Air conditioning makes oppressive odor more manageable. In the scene that is not air condition, the odors are overwhelming. At the latter scene, excessive perspiring makes investigators to work unintentionally faster … can flaw the investigation.

  17. Outdoor Crime Scenes • Huge environmental obstacles … affect the investigation. A scene in the woods differs from a shooting in a parking lot. • Scene in the mountains in the middle of winter with the temperature hovering in the 20oF range and after a snow storm has obstacles different than the same scene in the spring with the temperature in the 60’s. • A field of corn in May is different than the same field in late July. • The landscaped back yard of a residential house is different from an un-mowed field of knee high wheat. • Each has obstacles and each requires a strategy born from logic … to search correctly and efficiently.

  18. Searching With Purpose

  19. Systematic Search • Gardner suggests that a crime scene search should be methodical and systematic, and defines systematic as “purposefully regular”. … • Military & paramilitary agencies easy to implement … gives police/military investigators a way to standardize the search to accomplish a specific goal. • Accountability easier to control,… • Standardization gives the appearance of thoroughness. • In fact, the opposite may be the case.

  20. Method vs. Logical Searches • Method searches: A way to do something that is rote, repeatable and efficient. • Lead to thoughtless searches • Repeated at scene investigations throughout the U.S. • Immortalized in crime scene texts. • Logical Searches • Minimizes missed evidence • Minimizes collection of evidence that is not relevant • Rather than just methodical and systematic, the crime scene search should be logical (reasoned) and systematic.

  21. Logic Means Using reasoning to recognize relevant evidence.

  22. A Reasoned Approach • Scene search should be guided by the question of relevance, … refers to the relevant investigative questions. • Relevant investigative evidence leads to probative evidence • Answering these investigative questions determines how the search is conducted. • Inman and Rudin said, “searching is looking with purpose”, • This is not a method approach. • It is a reasoned approach.

  23. Innovative or Creative Searching • The most successful scene detectives and criminalists are innovative • Have an innate ability to think creatively. • Skill some learn or approximate over time through experience. • However, some “see” connections where others, even experienced investigators, do not. • Those possessing this ability are the best crime scene investigators.

  24. Named Search Methods

  25. Scene Search Methods • Typically presented as methods of choice in crime scene textbooks, … • Logic can replace all of them … • A certain aspect of truth with many. • Investigators have had success searching scenes … if had been a flop, there would be no reason for passing formats … workshops, training exercises or written format. • Method searches for indoor and outdoor scenes designed for specific situations … scene investigator decides which to use. • Thus looking for human remains in a public park and wooded area outside Washington DC might requires a different search strategy than that used to find fragments and body parts from an airplane, such as flight 93 that crashed in Pennsylvania on 9/11.

  26. Minimizing mistakes • Searching a wooded area … trees and shrubs offer challenges • Maintaining search line properly • Requires a logical and systematic process that milling around, for example, cannot deliver. • Searching an open field has no obstacles & are not restricting. • A proper search requires understanding what the scene is saying. • To many investigators, searching (an area), whether inside or outside, isn’t as sexy as other scene-related activities • Bloodstain pattern analysis, enhancing tire track impressions or dusting and lifting fingerprints. • Searching is sexy … if the team in synch with the scene, searching will suddenly rear its head and give that “Ah ha!” moment when something important is located, such as the evidence that will lead to a successful prosecution or the exoneration of a suspect.

  27. A logical and systematic search Best way to find objective evidence for court. • If haphazard or random, the risk is missing important evidence or, equally important, incorrectly assessing the scene correctly - finding a motive, linking evidence, interpreting the sequence of events, and etc. • Searching … ability to use their hands and powers of observation • Tendencies for bias, attention to detail and experience are on display. • Searching is one of the more critical functions of an investigation, Does critical adequately describe importance of scene search? • The Merriam Webster Online Dictionary defines critical “ • 1: of, relating to, or being a turning point of an important juncture.” Doesn’t this completely identify with the importance of the scene search. • When the search begins, the team enters a make or break point of the investigation because this is when it is looking to “make” the case.

  28. Basic “Method” Search Patterns • The “Method” Approach - • Grid • Strip/Line • Circle/Spiral • Ray • Zone • Link • Point-to-point

  29. Milling around An Un-method • Not systematic • Not logical • Not appropriate for any scene

  30. The Line (Grid) Methods • Diagrams of Grid/Line searches are self explanatory, • Little to need to explain the mechanism of how a search of this type might take place. • All “method” searches are roadmaps … • If followed correctly, the search will likely be conducted properly. • The grid is a two-step variant of simpler search types, which are conducted in typically one direction.

  31. Line Searches: • Unidirectional line searches lead to missed evidence, • Complicated areas where evidence may be difficult to see, e.g., woods, fields, etc. • On flat, uncovered surfaces that are small, • Concrete and paved parking lots where the line-of-sight is unhindered, these methods can be appropriate. • Nothing is lost, except time, by performing a perpendicular search - as in a grid. • Underwater searches Water Line Search

  32. Line (strip) Methods • Team Leader coordinates search • Mostly applicable to outdoor scenes • Useful for a few or a large number of searchers • May use untrained searchers • No boundaries make it difficult to search systematically • Large areas • Parks • Yards • Parking lots • Highways • fields End Start

  33. Line (Strip) MethodsContinued Depending on the nature of the scene, • Can mark-off or delineate lines/lanes searched • Ensure full coverage. • Divide the area into strips or lanes (north/south or east/west). • Assign teams to line up shoulder-to-shoulder (typically an arm’s length apart. • nature of the evidence dictates the separation between searchers at the start of a strip or lane. • Plane crash in a field • Body dumped in the woods End Start

  34. Parallel Search • Designed for smaller outdoor scenes. • Drawback of parallel & any one-time search • High possibility of missing evidence. Finish Start

  35. Grid Method - Modified Line • Modified double-line search • Searches area twice • Two different searches cover same area • Two eyes are better than one • Two lines created perpendicular to each other • Follow first line & search as in Line Method • Re-search @ right angles in the second line search End Start

  36. Grid Searches • The grid search … most appropriate variation of line/grid searches for outdoor environments … applicable to all environments. • Line search is variation of grid search, • Single-pass search • NEVER appropriate, because it misses evidence. • For large outdoor scenes, such as an airplane crash, it may be appropriate to grid the scene and then conduct individual grid searches within each major grid. • An example was the WTC scene after the 2001 attacks on the World Trade Center buildings. • The scene was gridded into 70 foot squares and each grid searched systematically. • That scene was different than most because each grid had 3D characteristics, surface and depth.

  37. The Sequence of Outdoor Grid Search • Photography • Establish scene boundaries • Identify an appropriate search method. • Searchers are at arm’s length distance apart in a line • Walk in straight line until an item of evidence found. • Line stops … mark evidence with evidence marker flag • Line continues until the search has been conducted. • Line turns and searches in perpendicular direction to give the scene a duplicate search. Individual searchers never search the same area twice. • Midrange photography of marked evidence • Close-up photography of marked evidence • Sketch the area, measuring and pinpointing evidence locations • Collect and package marked evidence • Transport the packaged evidence to the police department and/or crime laboratory

  38. Zone and Point-to-Point Searches • Appropriate for Indoor Scenes. • Zone Method: • A way to prioritize search areas, such as rooms in a house. Each room is a zone, and the attention it receives depends on scene circumstances. • Areas of most obvious activity are primary search areas. The zone where the body was found and the entrance and exit paths are prime search areas. • A bedroom that apparently had no activity might not seem as important, • Should be some discussion concerning whether it might have probative evidence and how much effort should go into searching it. In truth, no area of the scene should be ignored.

  39. Point-to-point Search • Small, confined areas and when a potential route of travel has been detected or is suspected. • Identify key locations or areas within the crime scene • Points of entry/exit, location of the victim, location of weapons, etc. • Thoroughly examine the pathways or routes • Connect the key locations to other areas where evidence may be found. • Fragile evidence • Evidence on the floor, • Footwear impressions, trace evidence, etc. and make every effort to avoid altering or destroying the evidence • Maintain a narrow path into and out of the scene. • Be cognizant of fragile evidence • Search each area by at least two investigators • In pairs & one after the other. A D B C Movement through scene Divided by quadrants

  40. Link MethodThinking the Search Footprint Window Fingerprint • Not geometric, • Not easily definable or random • Exploits 4-way linkage theory • Finds associations among • Scene • Victim • Suspect • Evidence • Logically systematic • Evidence associated with obvious activity • Each step based on findings & observations & applying logical progression • Expectation that evidence will be in “that” location • Homicide Example • Footwear & tire impressions along adjacent, logical pathways • Things missing from body • Consider secondary/staged scenes • Sexual Assault • Evidence Types • Semen • DNA • Bite marks • Amount & pattern of blood • Weapons • Fingerprints/DNA

  41. Wheel / Ray In a large area this method is a recipe for failure. • Essentially a circular search • Start @ critical point • Travel outward along straight lines (rays) • Difficult for searching large areas • Used only for special situations w/limited applications

  42. Spiral Search Patterns • Spiral search: • Investigator begins at the epicentre of the room and moves outwards in a spiral pattern. • Alternatively the investigator starts at the edge of the scene and spirals into the centre.

  43. Employing On-scene Technology • and/or Statements • Logic in action also means taking advantage of everything available to narrow the search area. • Using Technology: burglar caught on a surveillance camera …captured path through scene and areas touched. • Dramatically narrows search area … know how the burglar got inside the premise, movements, and what touched. • Areas not captured by the video must be searched. • Statements by witnesses and/or victims can also help narrow the search area. • If the victim of robbery tells investigators that the robber was not in certain areas of his store, searching them is waste of time. • Archiving still necessary.

  44. Pressure at the Scene • Exist on a multitude of levels • Media exerts own brand of pressure, such as hounding the team leader for information. • Team leader tied up with detectives … places a burden on team members. • Team size creates other pressures … small team may work well together … members have more work than those in a larger team. This creates a situation where rushing can create errors. This is a pressure with which the team leader must deal carefully. • Demanding superiors – police chief, the Mayor, etc. - create pressure to speed search and provide investigative information. • Environmental insults create pressures on outdoor scenes … destruction of evidence. • Political pressure @ new levels in high profile cases, e.g., police shootings, deaths of well-known individual and cases of bias.

  45. Constraints • Scenes have constraints … time. • Multiple constraints: • Workload, where the investigating unit has other scenes to investigate, • Weather • Geography • An example might be a fatal hit-and-run on a major thoroughfare during in rush hour, where there is not only time but other constraints: traffic, pedestrians, etc.

  46. Locating Trace Evidence at the Scene Areas of Macroscene Elements Knowing where to look. Not difficult, but can be elusive without a clear understanding of the scene characteristics.

  47. Technology to Aid Searching • Most search activity employs a visual examination of the scene. The wavelengths on ALS can help locate specific types of evidence. • Searching for Trace Evidence – Overview Considerations • A scene search does not end with picking up items only elements of the macroscene. • Also consider the invisible evidence. ALS helps locate invisible evidence, e.g., UV light (300-400 nm) aids in finding hairs and fibers and light at 450 nm will help locate fibers and some biological evidence. • Collecting trace evidence is critically important. Since it is mostly invisible to the naked and aided eye, collecting requires logical thought process of knowing where to look and then using standard techniques for collecting it. • Knowing where to look can be elusive if there is not a clear understanding of the scene characteristics: Logic in action. • Suffice to say, each scene represents a unique challenge.