Searching the Scene: Logic in Action Collecting evidence without a valid reason is also stupidity in action. 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 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. Archiving and Searching Common Scene Types Crime types … Each crime scene is unique Overlapping categories of evidence What starts as a burglary may become a homicide or a sexual assault Specific attributes may 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 Need to alert the team when possible evidence is found Evidence in Selected Case Types • Vehicle searches – Hit & run • Exterior/undercarriages/grill/headlights/bumper/windshield • Injuries to victim & operator of the vehicle – Tissue/blood on vehicle • • • • • Fingerprints – outside & inside Paint transfers – on clothing, to vehicle Fabric pattern transfers – to vehicle Trace evidence transfer – glass, hairs, fibers Blood, blood spatter • Homicides & Sexual assaults • • • • • • • Interior for blood/semen/trace evidence Blood and blood spatter GSR/Bullet path determination Fingerprints Trace evidence Saliva Vehicles often involved • Suicide • • • • Blood spatter/bullet path determination GSR Notes / family history Scene characteristics Processing Or Investigation? Scene investigation is NOT a blind endeavor Scene investigations are extremely complex Searching is crux of the investigation Definition of investigation is more rigorous and appropriate. “Processing” should be replaced with something that projects cognizant thought, such as investigation. 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” Investigation; “\Scene investigation and searching is more than a “process.” It is a scientific endeavor and investigation, and certainly more than a simple "process." 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 Original walk through with the first officer Archiving Why the Walk-Through? Observes and absorbs the macroscene elements 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 Why Archiving? Archiving gives the only pictorial perspective Illustrates how macroscene elements relate Shows the relative location of evidence If the archivists and team leader are in synch, information emerges from the chaos that is the hallmark of all crime scenes. What About Searching? The Scene Search Logic in Action The Meat and Potatoes An integral arm of scene management and archiving The team leader designs the search strategy based on logic Not on a "method" published in a text book o Proper search requires understanding of the scene Mental and physical activities are inextricably joined Scene Management The Investigative Glue Archiving (Video/Photo/Sketch) Eye for the Future Defining the Search Defining the Search Investigative team needs legal right to investigate The search begins when the team leader preforms a scene walk through “Sizes up” or takes inventory of the scene Assimilates first impressions Initial investigative strategy and precautions take shape Macroscene elements and other scene nuances absorbed Immediate Concerns Macroscene Elements Other Issues Size – physical terms Obstacles Relevant – Obvious Evidence Additional Resources Required Fragile Evidence Media Scope – Crime Type Primary/secondary/staged Command Center/Containment Modern Considerations Modern crime scene investigation texts often present as a “method.” They promulgate “named” procedures designed for specific crime scene types, such as for indoor and/or outdoor scenes. Intent of “methods” is not to convey simplicity Roadmap to minimize errors Minimizing errors is better accomplished in another way Successful Searches General Guidelines Attributes of a Successful Search Elements Effective Management Experience – knowledge – leadership Understanding the nature of the Scene Size, scope, weather, obstacles, on-scene environment, lighting, etc. Appropriate Logic Employing the scientific method Systematic approach Not random Creative thinking Relative associations of scene elements Effective Management Keeps the team focused Assigns roles Keeps the investigation on track Avoids roaming aimlessly Effectively managed teams are efficient and thorough 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 can affect the success 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. Outdoor Crime Scenes Huge environmental obstacles 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 Requires logic and reasoning Searching With Purpose Systematic Search Gardner suggests - search should be methodical and systematic “Purposefully regular” Military & paramilitary agencies easy to implement A way to standardize Accountability easier to control Standardization gives the appearance of thoroughness In fact, the opposite may be the case Method vs. Logical Searches Method searches: A way to do something that is rote, repeatable and efficient Leads 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 Logic Means Using reasoning to recognize relevant evidence A Reasoned Approach Guided by the questions of relevance 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! Innovative or Creative Searching Innovative and creative Innate ability to think creatively May be learned over time through experience “see” connections where others do not. Those possessing this ability are the best crime scene investigators Named Search Methods 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 Method searches Designed for specific situations (indoor or outdoor scenes) Scene investigator decides which to use Minimizes mistakes Requires logic as well 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 A logical and Systematic Search Best way to find objective evidence 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. Basic “Method” Search Patterns The “Method” Approach Grid Strip/Line Circle/Spiral Ray Zone Link Point-to-point Milling around An Un-method Not systematic Not logical Not Methodical Not appropriate for any scene The Line Methods Diagrams of Grid/Line searches are self explanatory 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 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 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 o o o o o Parks Yards Parking lots Highways fields Start End Line (Strip) Methods 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 shoulderto-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 Start End Parallel Search Designed for smaller outdoor scenes Drawback of parallel & any onetime search High possibility of missing evidence Finish Start Grid Method - Modified Line Modified doubleline search Searches area twice Two different searches cover same area Two eyes are better End 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 Start Grid Searches The most appropriate variation of line/grid searches for outdoor environments Line search is variation of grid search Single-pass search o Easy to miss evidence Able to section scene For large outdoor scenes Conduct individual grid searches within each major grid or section 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 The Sequence of Outdoor Grid Search Photography Establish scene boundaries Identify an appropriate search method(s) 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 Zone and Point-to-Point Searches Appropriate for Indoor Scenes Zone Method: Allows you to prioritize search areas 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 The entrance and exit paths A bedroom that apparently had no activity might not seem as important Should be some discussion and searched - no area of the scene should be ignored Zone Search Bthrm Zone C • Scenes with readily definable Zones • Search each zone @ least 2x • Variety of alternatives to this approach Bedroom Zone E Bedroom Zone D Dining Room Zone D Patio F Kitchen/Living Room Zone A Foyer Zone B Walkway to Main Entrance Zone F – Each zone searched systematically – Indoor scenes • Zones can be subdivided • Zones can be prioritized Macroscene Elements 1. 2. 3. 4. Body in Bedroom B Bloodstains in Kitchen & Bathroom Dust footwear impressions in Foyer Broken window at front door – Location of body – Entrance points/exits – Other targeted areas 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 A 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, D B 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 C investigators In pairs & one after the other Movement through scene Divided by quadrants Link Method Thinking the Search Footprint Not geometric Not easily definable nor Scene Victim Suspect Evidence Footwear & tire impressions along adjacent, logical pathways Things missing from body Consider secondary/staged scenes Sexual Assault Logically systematic Evidence associated with obvious activity Each step based on findings & observations & applying logical progression Expectation that evidence will be in “that” location Fingerprint Homicide Example random Exploits 4-way linkage theory Finds associations among Window Evidence Types Semen DNA Bite marks Amount & pattern of blood Weapons Fingerprints/DNA 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 Spiral Search Patterns Spiral search: Investigator begins at the epicenter 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. Employing On-scene Technology and/or Statements Logic in action 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 can be a waste of time Archiving still necessary Pressure at the Scene Exist on a multitude of levels Media Detectives Team size Demanding superiors Environmental factors Political pressure Constraints Scenes have constraints: Time 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. Locating Trace Evidence at the Scene Areas of Macroscene Elements Location Points of entrance and egress Areas of a struggle The clothing and shoes of participants in the crime (victims and suspects) Furniture - understanding the transfer potential of certain fabrics Bodies of decedents Fingernails Areas searched by perpetrator Reason These are areas where the perpetrators might have been and can be locations of fibers, hairs, etc. These areas are prime targets for hairs fibers, blood and saliva. They include furniture and carpets and should not be overlooked. The clothing of victims and suspects in direct contact with each other should have fiber, hair, saliva, and blood evidence present. Fabric furniture involved in a struggle (turned over chairs, etc) has the potential of attracting fibers and hairs. The likelihood depends on the characteristics of the fabric – whether it accepts and/or gives up its fibers readily. These can also have saliva and blood. The body, its clothing. Anyone involved in a struggle has the possibility of having trace evidence under the fingernails: hairs, fibers, saliva and blood. If a perpetrator, e.g., a burglar, is searching for valuables, the areas searched are prime targets for trace evidence. 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. Using the ALS to Locate Evidence Wavelength (nm) Application Goggles White Light General scene scanning Fingerprints on shiny surfaces Blood on shiny and dark surfaces Long Wave UV 300-400 Hair, fibers, fluorescent materialpowders Body fluids/bruises/bite marks/ Food stains (tomato based fluoresce) Clear or Yellow 415 Bloodstains (absorbed :appears dark) Food stains (tomato based) Clear 450 General scene scanning for Body Fluids, semen blood Powders/Teeth/Bones Paint/fibers/accelerants Orange 465-485 Fluorescent materials/powders Body fluids Orange 515-535 Super glue fumed fingerprints Body fluids Red (Clear for body fluids) 570 Inks Clear Red Collecting Too Much Evidence Tape lifts of trace material from furniture in a living room, a conversation might go something like this; this could be a phone conversation or could take faceto-face. Understand that a phone conversation like this might take place days or weeks after the evidence had been submitted to the laboratory. How Much Evidence to Collect Scientist: “You sent 175 tape lifts from furniture taken from the Dracula scene. I gotta tell ya, there’s no way I do all that work in my lifetime. Why so many?” Investigator: “I took what I thought was important for the investigation.” Scientist: “I understand (thinking the investigator is doing CYA), but is there some priority here?” Investigator: “They were in the room where the murder took place.” Scientist: “Hmm … Each piece of furniture has a an evidence item number. Evidence was collected from 10 pieces of furniture. Were they all directly involved in the struggle? Investigator: Lemme check the scene photos. Scientist: OK. Investigator: The struggle mostly took place in one area of the living room, probably on the sofa, Item number 4. Scientist: OK. I’ll start there. What else? Investigator: A chair near the sofa had been knocked over. It, too, might be a possible. Item number 7. Scientist: Thanks, I’ll look at both of them. I’ll let you know what I find, and we can decide where to go from there. Investigator: OK, sounds good.