Crime Scene Search Methods and Patterns: Types and When to Use With Examples

What is Crime Scene Search?

A Crime Scene Search is a systematic method designed to locate evidence within a crime scene or other areas where evidence might be present. This process typically involves:

• Dividing the search area into manageable segments.
• Adapting the search pattern to suit the specific area, available personnel, time constraints due to weather and lighting, and the unique circumstances of each crime scene.

In other words, it is a technique used to comprehensively search the area to uncover potential evidence that helps in solving cases.

What is a Need for Crime Scene Search?

Forensic science is a scientific study. So, every element of it needed to be scientific or systematic.

This is also true for crime scene searches. 

Investigators need to follow certain patterns and protocols of searching so that they can rely on their findings and what evidence leads the case. And this is what crime scene searches do.

Let’s assume if there are no set protocols for searching, there might be a chance that potential evidence could be missed that hampered the investigation.

Here are some key elements that state why a crime scene search pattern is needed.

• Understanding the crime scene and what needed to focus on. For example, in a single center point in a confined area, wheel search is preferred.
• Defines where to look for evidence and what any anomalies or inconsistencies in a crime scene indicate. It helps in reconstruction.
• Using proper crime scene recording, the location of evidence can be established even if the evidence is located far from the crime site.
• An efficient and effective way to save time without compromising the investigation process.
• Help in the learning process for new crime scene examiners (CSE) or investigators.

10 Types of Crime Scene Search Methods and Patterns

There are mainly 10 types of crime scene searches and patterns. These are listed below in tables with examples:

Types of Crime Scene Searches	When to Use	Examples
Preliminary Search	Every crime scene	Overview of crime scene
Intensive Search	Mostly every crime scene	Finding hidden evidences
Link (Point-to-Point) Search	Multiple points of interest	Searching main evidences to a crime
Strip and Lanes Search	Large open area without barriers	Searching in parks or parking lots
Line Search	Large open elongated area with barriers	Searching in woods
Spiral Search	In confined and open space	Searching in room with center point or open water search
Grid Search	When evidence scattered over an area	Bus or plane crashing site
Zone Search	Complex and indoor crime scenes	Searching a multi-room building
Wheel or Ray Search	Outdoor scenes	Searching for a missing person from a center of point
Vehicle Search	Vehicle as evidence	Finding evidence related to crime

1. Preliminary Search Method

The initial quasi-search focuses on identifying obvious items of evidence, such as weapons, broken objects, or visible traces. It is usually done before actual documentation of the crime scene.

This search serves orientation purposes, helping investigators familiarize themselves with the crime scene layout before documentation begins.

The preliminary search allows investigators to formulate an initial understanding of the crime, guiding their approach to the subsequent intensive search.

Advantages:

• Relatively quick and efficient.
• The best strategy to start documentation of any crime scene.
• Identify key pieces of evidence.
• Helps investigators familiarize themselves with the crime scene.

Disadvantages:

• Limited in-depth analysis.
• May not uncover less obvious or hidden evidence.
• The focus on more apparent items might lead to inadvertent contamination of other evidence.

2. Intensive Search Method

The intensive search is conducted after documentation, including photographs, sketches, and notes, but before the actual collection and packaging of evidence begin. They are used in conjunction with other searches (listed later in the post) such as zone, grid, and spiral.

They are proven more appropriate in indoor or crime scenes with confined areas and lots of items.

Intensive searches have a level of intrusiveness; Move from least intrusive to more intrusive to avoid damaging evidence. Here are examples of various levels of intrusiveness:

a. Least Intrusive Search Method: It includes searching the crime scene with the naked eye or lighting tool (ALS), without touching any items and then documenting and collecting.

b. More intrusive Method: After initial documentation and collection, items like furniture, clothes, or other objects are moved to uncover hidden or less obvious items.

c. Most intrusive Method: It involves damaging or destroying items within the crime scene to collect evidence. For Example: cutting holes in the wall to recover projectiles, cutting pieces of carpet with bloodstain pattern, etc.

Note: Make sure you document and photograph before and after each level of intrusive search and damages to the crime scene.

 Advantages:

• Recovery of hidden evidence that may be missed during the preliminary search.
• A thorough examination of the crime scene.
• Can be related to accurate and complete investigation.
• Reduce the risk of important evidence left behind.

Disadvantages:

• Can be time-consuming especially if there are too many items and hidden places.
• Documentation and photographing each level of intrusiveness during the search is time-consuming.
• Some evidence requires trained officials to avoid contamination.
• Require additional resources such as a specialized CSE and specialized equipment.
• The most intrusive searches may require physically damaging the crime scene items.

3. Link (Point-to-Point) Search Method 

Link search methods focus on following a trail of evidence by first evaluating the various focus points within the crime scene and then documenting and communicating successively.

In this method, the search begins from the first point of interest such as the front door or evidence, and processes to the next point of interest. This continues sequentially until all interest points get covered.

Appropriate Crime Scene Situation to Use In:

• This method is suitable for crime scenes with multiple points of interest and a need to establish clear paths for investigators to follow.

Advantages:

• Helps establish clear walking paths, minimizing loss or destruction of evidence.
• Allows a systematic search focused on multiple points of interest within the crime scene.

Disadvantages:

• Can be time-consuming, especially if there are many points of interest.
• Requires careful attention to avoid straying away from established pathways.
• May not be suitable for crime scenes with few interest points.

4. Strip (Lane) Search Method

The strip or lane search method involves dividing the crime scene into narrow strips or lanes. Each team member is responsible for searching their assigned lane and turning around and walking in the opposite direction to the next strip or lane.

Investigators needed: One (in strip method), while more than one (in lane search method).

Strip Vs Lane Search Method: Know the difference between strip and lane search methods. Check article Strip (Lane) Search Pattern: Procedure, When to Use? With Examples

Appropriate Crime Scene Situation to Use In:

• Large areas or expansive crime scenes.
• Open areas where visibility is generally unobstructed such as parks.

Advantages:

• Ensures systematic coverage of large or open areas.
• Can be easily extended to cover multiple rooms or areas within a given scene.
• Provides a clear and organized search pattern, reducing the risk of missing crucial evidence.

Disadvantages:

• Requires a sizable team of investigators for efficient execution.
• Can be time-consuming, particularly for very large crime scenes.
• Less suitable for irregularly shaped or indoor crime scenes.

5. Line Search Method

The line search method is a variation of the strip/lane search. There is only one main difference between the two i.e. in line search methods, multiple searchers are walking across the crime scene in straight lines and don’t turn back. 

They continued their path to the other side of the crime scene. While in strip or lane methods, searches turn around and continue to search in the adjacent strip or lane.

Investigators Needed: One per line.

Appropriate Crime Scene Situation to Use In:

• Best suited for outdoor crime scenes involving rough or uneven terrain, where it might be challenging to physically mark lanes or strips.
• Linear or elongated crime scenes such as roadsides, and alleyways.

Advantages:

• Suitable for outdoor crime scenes with difficult terrain.
• Enables simultaneous searching by multiple investigators, potentially expediting the search process.
• Provides a systematic approach, reducing the risk of overlooking evidence.

Disadvantages:

• Requires a larger team of investigators or searchers for efficient execution.
• Can be challenging to maintain a straight alignment and consistent search direction due to terrain.

6. Spiral (Circle) Search Method

As the name suggests, the crime scene is searched in circular motion either from the center of the scene (outward spiral) or from the outer perimeter to the center of the scene (inward spiral). 

With each turn, the searcher either has to move outward or inward while searching for evidence. If the searcher feels dizziness due to circular movement, make sure to take rest.

• Other Names: Circle Search Method
• Investigators Required: Only one

Appropriate Crime Scene Situation to Use In:

• An inward spiral method is preferred in confined, small, confined, or smaller areas.
• An outward spiral method is preferred when crime scenes have no outer perimeter such as open water.

Advantages:

• One searcher is needed.
• A way of thoroughly searching crime scenes.

Disadvantages:

• Searchers need to pay constant attention.
• Can cause disorientation due to circular motion.
• Investigators have to follow their imaginary spiral lines which can lead to missing some evidence.

Read More: Spiral (Circle) Search Patterns: Procedure, When to Use With Examples

7. Grid Search Method

The grid search method is a variation of the strip search method, where the area is searched twice in two perpendicular directions, ensuring a more thorough examination of the crime scene.

In this systematic approach, investigators start walking in a designated lane in one direction (e.g., north to south ). After completing, turn around at a 90° angle and continue (east to west).

• Other Names: Modified line method or Double-line search
• Investigators needed: One investigator

Appropriate Crime Scene Situation to Use

• This method is well-suited for large, open areas and outdoor crime scenes.
• Where evidence may be scattered over a definitive wide area, such as fields or parking lots.

Advantages:

• Ensures thorough coverage by searching the area twice in perpendicular directions.
• Minimizes the chances of missing crucial evidence.

Disadvantages:

• More time-consuming due to double search.
• Requires significant manpower for optimal efficiency.
• Physically marking in two stages also increases the risk of contaminating the crime scene.

8. Zone Search Method

The zone search pattern method divides an extensive crime scene into smaller sections or quadrants. Each investigator is assigned to search a specific quadrant or zone, ensuring a comprehensive search.

• Other Names: Map Grid or Quadrant searching
• Investigators Needed: Depends on crime scene needs

Appropriate Crime Scene Situation to Use In:

• Ideal for large interior or exterior scenes or vehicles that require a need of dividing crime scenes into zones.
• For example, effective in houses or buildings with rooms.

Advantages:

• Enables a more organized and systematic search of extensive crime scenes.
• Use of other search methods such as strips, and spirals in each zone for thorough coverage.
• Facilitates tracking of which zones have been searched and by whom, ensuring no areas are overlooked.

Disadvantages:

• Can be time-consuming, particularly for very large or complex crime scenes.
• Requires proper documentation and labeling of zones to avoid confusion or overlap.
• A larger team of investigators may be required for efficient execution.

9. Wheel or Ray Search Method

The wheel or ray search method is used in crime scenes with a central point of interest. From the central points, searches have to move in a straight ray looking for evidence.

You can understand the wheel/ray search method as a wheel whose center axis represents the central point of interest and each spoke represents the ray that needs to be followed by the searcher.

• Other Names: Radial, Spoke, or Ray search pattern method
• Investigators Needed: One per ray (Ideal at least 6)

Appropriate Crime Scene Situation to Use In:

• Small crime scenes with limited area.
• Larger scenes such as grasslands in searching for bodies.
• Situations where a quick initial search is needed. Eg: a missing person from his trip to the forest.

Advantages:

• Cover a large area in a short time.
• Easy to organize.
• No marking zones or lines.

Disadvantages:

• Higher chance of losing potential evidence.
• Not suitable for crime scene searches with scattered evidence.
• Need of secondary search from other searching methods.

10. Vehicle Search Methods

A specialized way of searching a vehicle for evidence either because of linking them to a crime scene or suspecting of illegal transport goods. In most cases, vehicle searches are usually done in zones.

There are three main parts of vehicle searches: preliminary, exterior, and interior searches.

• Preliminarily deals with finding any evidence near the vehicle such as shoe prints near a pickup truck
• Exterior vehicle searches include finding evidence on the exterior of the vehicle such as damage signs, accident marks, scratches, paint transfers, etc.
• Interior searches include finding evidence on the interior of vehicles such as finding fingerprints on front dashboards, blood-soiled clothes, etc.

Read More: How to Search Vehicles for Evidence? A Practical Guide and Tips

Who Should Choose to be a Crime Scene Searcher? 

Following are the some of deciding factors in choosing a searcher during a crime scene search:

• Education and Training: He/she should have a background in forensics or the justice system or have undergone specialized training in crime scene investigation.
• Experience: Prior experience is always preferred if you have options.
• Emotional resilience: Some crime scenes are emotional or religious driven. A crime searcher must value evidence or facts over their emotions.
• Maintain the integrity of evidence: He or she properly knows how to document, collect and preserve various types of evidence without damaging their values.

Why is it not advisable to use Citizens for searching for some crimes?

In some cases, such as missing persons in forest areas need to rescue asap, in those cases, police need more manpower and that is why they include citizens from local communities to search the area.

This is quite a good option but it leads to many other problems. These are:

• Risk of involvement of perpetrators as a searcher: This may lead perpetrators to compromise the investigation.
• Lack of expertise to handle evidence: Citizens may not have the experience to conduct a crime scene search and handle evidence. This leads to contamination of potential evidence.
• Emotional involvement: Some of the citizens might have a personal connection to victims or suspects that can deliberately bias their actions and judgment during the search.
• Legal Issue: Destruction or contamination of potential evidence by a citizen can lead to the removal of that evidence from the case, and the loss of its evidentiary values.

So, it is better, whenever possible, not to involve any citizen in crime scene searches. All citizens or reporters should be bound behind the yellow crime scene tapes.

References:

• Expertise in crime scene examination: comparing search strategies of …[DOI]
• UAV‐assisted real‐time evidence detection in outdoor crime scene investigations [DOI]
• Henry Lee’s Crime Scene Handbook By Henry C. Lee, Timothy Palmbach, Marilyn T. Miller [link]
• Crime Scene Forensics: A Scientific Method Approach By Robert C Shaler [link]
• An introduction to crime scene investigation: AW Dutelle by Jones & Bartlett Learning
• Intelligent indexing of crime scene photographs by K. Pastra; H. Saggion; Y. Wilks [link]
• A Comparative Study: The Effectiveness of Various Search Strategies for Finding Critical Evidence in Crime Scene Analysis by Elianna Tracy, Spring Valley High School [link]
• Crime Scene Processing and Investigation Workbook, Second Edition By Christine R. Ramirez, Casie L. Parish-Fisher [link]
• Crime Scene Management within Forensic science [link]