Searching the Scene: Logic in Action

Collecting evidence without a valid reason is also stupidity in action.

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.

2. Homicide cases: Violent dispute between spouses, A shooting in a drug case

Searching: A Philosophy

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.

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.

Archiving and Searching Common Scene Types

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

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.

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;“

Scene investigation and searching is more than a “process.” It is a scientific endeavor and investigation, and

certainly more than a simple "process."

Processing Or Investigation?

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.

What is the Scene Search?

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

Why the Walk-Through?

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.

Why Archiving?

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. o 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

The Scene SearchLogic in Action

The Meat and Potatoes

What About Searching?

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.

Defining the Search

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

Immediate Concerns

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.

Modern Considerations

Successful SearchesGeneral 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

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.

Effective Management

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.

Indoor 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.

Outdoor Crime Scenes

Searching With Purpose

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.

Systematic Search

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.

Method vs. Logical Searches

Logic Means

Using reasoning to recognize relevant evidence.

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.

A Reasoned Approach

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.

Innovative or Creative Searching

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.

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.

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.

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.

A logical and systematic search Best way to find objective evidence for court.

Basic “Method” Search Patterns

• The “Method” Approach - – Grid– Strip/Line– Circle/Spiral– Ray– Zone– Link– Point-to-point

Milling around An Un-method

Not systematicNot logicalNot appropriate for any scene

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.

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 areaso Parkso Yardso Parking lotso Highwayso fields

Start End

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 fieldBody dumped in the

woods

Start End

Parallel Search

Start

Designed for smaller outdoor scenes.

Drawback of parallel & any one-time search

High possibility of missing evidence.

Finish

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

Start

End

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 searcho 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.

Grid Searches

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

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.

BedroomZone D

Bedroom Zone E

Dining RoomZone D

FoyerZone B

Kitchen/Living RoomZone A

Walkway to Main Entrance

Zone F

• Scenes with readily definable Zones

• Search each zone @ least 2x

• Variety of alternatives to this approach– Each zone searched

systematically– Indoor scenes

• Zones can be subdivided

• Zones can be prioritized

– Location of body– Entrance points/exits– Other targeted areas

BthrmZone C

PatioF

Zone Search

Macroscene Elements1. Body in Bedroom B2. Bloodstains in Kitchen & Bathroom3. Dust footwear impressions in Foyer4. Broken window at front door

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

B

C

D

Movement through sceneDivided by quadrants

Link MethodThinking the Search

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

Footprint Window Fingerprint

Wheel / Ray

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

In a large area this method is a recipe for failure.

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.

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.

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.

Pressure at the Scene

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.

Constraints

Location ReasonPoints of entrance and egress These are areas where the perpetrators might have

been and can be locations of fibers, hairs, etc. Areas of a struggle These areas are prime targets for hairs fibers, blood

and saliva. They include furniture and carpets and should not be overlooked.

The clothing and shoes of participants in the crime (victims and suspects)

The clothing of victims and suspects in direct contact with each other should have fiber, hair, saliva, and blood evidence present.

Furniture - understanding the transfer potential of certain fabrics

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.

Bodies of decedents The body, its clothing. Fingernails Anyone involved in a struggle has the possibility of

having trace evidence under the fingernails: hairs, fibers, saliva and blood.

Areas searched by perpetrator If a perpetrator, e.g., a burglar, is searching for valuables, the areas searched are prime targets for trace evidence.

Locating Trace Evidence at the SceneAreas of Macroscene Elements

Knowing where to look. Not difficult, but can be elusive without a

clear understanding of the scene characteristics.

Technology to Aid SearchingMost 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.

Wavelength (nm) Application Goggles

White Light General scene scanningFingerprints on shiny surfacesBlood on shiny and dark surfaces

Clear

Long WaveUV

300-400

Hair, fibers, fluorescent material-powdersBody 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 bloodPowders/Teeth/BonesPaint/fibers/accelerants

Orange

465-485 Fluorescent materials/powdersBody fluids

Orange

515-535 Super glue fumed fingerprintsBody fluids

Red (Clear for body fluids)

570 Inks Red

Using the ALS to Locate Evidence

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 face-to-face. Understand that a phone conversation like this might take place days or weeks after the evidence had been submitted to the laboratory.

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.

How Much Evidence to Collect