CSI: Sketching and Mapping

How does the initial responding officer set the stage for successful crime scene processing?

Establishing control of the scene

5 goals of incident management the initial responding officer is responsible for in order to safely/effectively gain control of the scene

1. Document provided information

2. Not becoming a casualty

3. Provide for emergency care

4. Secure and control the scene and those within it

5. Release the scene to the appropriate authorities (detective or CSI)

Initial responding officer order of responsibility

1. Safety

2. Lifesaving

3. Scene control

What’s more important: lifesaving or evidence preservation?

lifesaving

3 points the primary officer needs to consider in order to secure/control the area

1. Primary focal points

2. Natural Entry and Exit Points

3. Secondary Scenes

Primary focal points

Areas that stand out within a scene

3 examples of primary focal points

a body, fired cartridge casings, a ransacked room

Natural Entry and Exit Points

Can determine where perpetrators enter and exit the scene

Secondary Scenes

Areas on the outer edge of/surrounding the scene

Suspect staging areas

a secondary crime scene where a suspect prepares or alters things related to the crime

Items dropped when the suspect fled a crime scene is considered…

a secondary crime scene

Who is responsible for the initial documentation of a crime scene?

The responding officer

Initial documentation of a crime scene includes

1. Who said what upon arrival

2. Noting transient evidence (smells, sights, sounds)

3. Times when ppl arrive or leave the scene

How is a scene physically secured?

Barrier tape

A designated ___ and ___ point should be a established

exit and entry point

Once CSI arrives, the first responding officer should…

conduct a debriefing

Purposes of the debriefing between the 1st responding officer and CSI is to consider (5things)…

1. Scope of the scene

2. Scene integrity and contamination control

3. Team approach and composition

4. Search methods to be used

5. Personal protective measures

Primary goal of scene processing

collect as much evidence as possible in the most pristine conditions

Multilevel Containment System

An effective way to maintain science integrity and reduce contamination by establishing at least two perimeters, creating 3 distinct zones (inner, middle, and outer)

Multilevel Containment System: Outer Area

typically where onlookers, media and non-essential personnel are kept

Multilevel containment system: middle area

A working zone that serves as a staging area for equipment such as cameras, bulky gear, or investigative kits. May also be used for trash collection and temporary evidence storage.

Multilevel containment system: Inner Area

Restricted to personnel actively involved in scene processing

CSI: Assessing

Before taking any action, the CSI must assess the circumstances to determine an appropriate course of action

CSI: Observing

The CSI visually inspects and mentally registers the condition of the scene and any artifacts present

CSI: Documenting

Documentation includes a variety of methods such as written notes of observations, photography, video recordings, and sketch creating

CSI: Searching

Always intrusive, involves moving items to examine surfaces that aren’t visible

CSI: Collecting

The physical removal of items at the scene is intrusive

CSI: Processing/Analyzing

Involves applying methods such as fingerprint powder, chemical enhancements, or other forensic techniques

CSI series of 6 systematic actions to handle and preserve evidence

1. Assessing

2. Observing

3. Documenting

4. Searching

5. Collecting

6. Processing/Analyzing

4 factors considered when determining the area/search swath a single searcher is responsible for

1. Nature of Ground Being Searched

2. Lighting

3. Environmental Conditions

4. Size of Items Being Searched for

Example of the nature of the ground being searched

An asphalt parking lot may be easier to search than a field of knee high grass due to visibility and surface uniformity

Ambient lighting and the time of day

are lighting conditions that will significantly affect a searcher’s ability to visualize evidence

Poor lighting conditions may…

obscure small or subtle evidence

On-scene environmental conditions (2) of INDOOR scenes that can impact focus and efficiency

1. temperature extremes

2. strong odors

On-scene environmental conditions (3) of OUTDOOR scenes that can impact focus and efficiency

1. Rain

2. Snow

3. Wind, etc

Example of how the size of an item being searched for effects CSI

searching for a small fired cartridge case on a mowed lawn requires more precision than searching for a larger item, like a pistol, in the same area

Circle/Spiral Search: Commonly used for…

interior scenes

Circle/Spiral Search

The searcher begins on the outer edge of the area and moves inward in a slow, controlled spiral pattern (can be conducted in reverse)

Circle/Spiral Search Key Consideration

maintain a consistent pace to ensure thorough coverage and minimize the risk of overlooking evidence

Strip Search is commonly used for…

exterior scenes when evaluating large areas

Strip Search

The searcher begins at one end of a designated strip and proceeds in a straight line to the opposite end, then moves to the next adjacent strip and continues in the reverse direction

Strip search pattern ensures…is particularly effective for…

systematic coverage of the entire area and its particularly effective for open fields, parks or large outdoor scenes

Line Search

Variation of strip search, the difference is the number of searchers involved. A group of searchers forms a line across an area, each responsible for a specific lane. The team moves together in a single direction, systematically scanning their assigned lanes.

Line searching is useful for….

large outdoor scenes w uneven terrain

Line search key consideration

team moves as a unit, maintaining the pace set by the slowest searched to ensure thorough coverage

Grid Search

Variation of the strip search where the area is divided into two sets of strips/lanes that intersect at 90-degree angles. The searcher conducts a standard strip search up and down each lane. Then perform a second search along the perpendicular set of lanes to create double coverage.

Grid search method provides more ______ than strip search

detailed examination

Zone Search

Two variations-small/confined spaces and large exterior scenes-where the space is divided into manageable zones and each zone is thoroughly searched before moving onto the next.

Zone search for small/confined spaces

ideal for areas that are difficult to search using patterned movements (inside a car)

Large exterior scenes

area is divided into physical grids or zones. particularly useful for extensive outdoor scenes with scattered evidence, remains or debris (airplane crash)

Point to Point Search

Rarely practiced in US. CSI identifies primary focal point and determines which order to process them. The investigator fully processes the first focal point and its surrounding area before moving onto the next. Without proper training and experience this method can become disorganized

Manual mapping methods allow for documenting (3)…

1. size of the scene

2. elements within the scene like furniture

3. precise location of evidence

Three people in a typical sketching and mapping team

Two take measurements and one makes the rough sketch

Baseline Coordinates are best suited for…

exterior scenes without obvious landmarks

Baseline Coordinates

Begins at datum point established by triangulating nearby landmarks. Tape measure is extended along the cardinal direction from this point and the distance to each item is measured at right angles. CSI records the position along the baseline where evidence measurements intersect.

Rectangular Coordinates are best suited for…

crime scenes with clear boundaries like interior walls

Rectangular Coordinates

CSI fixes evidence by measuring right angles from the evidence to the surrounding walls. Typically two measurements to the center of the item are taken. For regularly shaped items (furniture) two measurements from different points can be taken.

Rectangular Coordinates are ____ compared to triangulation

less precise

Triangulation is the…

most effective method for fixing evidence.

Triangulation: Regularly shaped items

CSI uses a minimum of four measurements from two distinct landmarks in the room to two points on the item for regularly shaped items.

Triangulation: Irregularly shaped items

(like a pile of clothes) two measurements to the center mass as sufficient.

Polar Coordinates: A _____ technique used for…

An older technique used for mapping large, open exterior scenes where evidence is scattered, such as airplane crashes or bombing scenes

Polar Coordinates

Using a sighting device, 2-3 measurements from a known point are taken to the evidence (horizontal distance, horizontal angle and elevation distance)

The amount of effort devoted to creating a sketch depends primarily on (2)…

1. severity of the crime

2. important of evidences spatial relationships

Formal Sketch 5 Basic Elements

1. Heading

2. Diagram Area

3. Legend

4. Title Block

5. Scale and Direction Notations

Formal Sketch Heading

a notation that explains the purpose of the sketch and why it was created

Formal Sketch Diagram Area

The actual drawing of the scene showing layout and evidence

Formal Sketch Legend

A key that explains symbols, labels or markings used in the diagram

Formal Sketch Title Block

Relevant information like location of the scene, date, and name of the artist

Formal Sketch Scale and Direction Notations

indicates whether a scale is used and specifies the ratio. shows the orientation of the sketch relative to compass directions

Standard Crime Scene sketch view

birds-eye view showing only horizontal surfaces and evidence on them

cross-Projection/exploded sketch

combines birds eye view of horizontal surfaces with the walls “laid down” flat to show evidence on vertical surfaces

Elevation Sketch

Provides a side view of a specific portion of the scene, like an interior wall or other vertical structure. Used to map and document evidence on walls

3D Sketch

Offers a more realistic perspective by presenting the scene in 3D. helps visualize spatial relationships more accurately

Spiral/Circle Search Pattern

Strip Search

Line Search

Grid Search

Baseline Coordinates