Crime Scene Search Methods

About the Author

Meera S Gopan, currently LLM Scholar at National University of Advanced Legal Studies Kochi, had completed her unitary LLB degree from Government Law College Thiruvananthapuram in 2024 and she also holds a B Tech civil engineering degree from Kerala University.

Introduction

Crime is the intentional commission of an act usually deemed socially harmful or dangerous and specifically defined, prohibited, and punishable under criminal law. A crime scene is any location that may be associated with a committed crime. Crime scenes contain physical evidence that is pertinent to a criminal investigation. This evidence is collected by crime scene investigators (CSI) and law enforcement. The location of a crime scene can be the place where the crime took place or can be any area that contains evidence from the crime itself. Scenes are not only limited to a location, but can be any person, place, or object associated with the criminal behaviors that occurred.

Crime scenes can be classified in many ways. First, crime scenes can be classified according to the location of the original criminal activity. This classification of the crime scene labels the site of the original or first criminal activity as the primary crime scene and any subsequent crime scenes as secondary. This classification does not infer any priority or importance to the scene, but is simply a designation of sequence of locations. Based on the size of the crime scenes, they are classified into microscopic and macroscopic. In macroscopic crime scenes, it will be composed of many crime scenes while n microscopic crime scenes, the importance is given to specific types of physical evidences found at macroscopic crime scenes.

Types Of Crime Scene Search Methods

Crime scene investigation involves locating, collecting, and interpreting evidence found at the scene of a crime. To do this, forensic experts or forensic science specialists are necessary. Forensic science utilizes scientific methods or techniques to interpret evidence during investigations. Often, a special unit of forensic technicians enters a crime scene to properly perform the collection, documentation, and preservation of evidence such as blood, fingerprints, etc. The gathered evidence is then examined and analyzed to help determine exactly what happened at the time of the crime.

The Crime Scene is searched for the physical evidences (visible or invisible). There are various types of search methods employed by the investigating officers and the forensic scientists at the scene of crime. The searching methods mainly depend on:

Type of Crime (Rape, murder, burglary, theft, etc.)
Nature of Crime (Homicide, suicide, or accident)
Size of the crime scene (macroscopic or microscopic)
Location of the crime scene (indoor, outdoor, combination of indoor or outdoor, or any remote area like underwater, desert, etc.)
Complexity of the crime scene.

Irrespective of the type of crime scene, the investigator has to decide the appropriate method immediately, without delay, so as to collect the evidences in the intact form as far as possible. Following are the basic search methods, usually commissioned on the crime scene:

1. Zonal Method

In this method the crime scene is virtually divided into different zones. The number of zones depends upon the size and complexity of the crime scene. This method can be applicable to both indoor and outdoor crime scenes. Different people will be employed in individual zones, and will search their zones thoroughly for the evidences normally as well as using different techniques (UV/IR/Video). After searching in their own zones, the zones will be exchanged to check the accuracy and double check for any missing items. This method cannot be applicable on very squeezed and complex crime scenes like elevators, lift shafts, or stairs.

The advantages of this method include:

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.

The disadvantages of this method include:

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.

2. Strip or Parallel Method

In this method the virtual strips or line are being imagined to walk through on the crime scene and look for the evidences. The method is well suited for the crime scene like class rooms, where rows are present already, each row can be considered as a strip. Also, minimum number of the personal are required for this method. One person will start the walk through from one corner of the strip and will move towards the other looking for the evidences. The walk through should be slow and thorough. If two personals are employed, then each of them can start from two different points and continuing to the different ends to double check the search.

The advantages of this method include:

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.

The disadvantages of this method include:

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.

3. Grid Method (two parallel strip)

It is just like the strip method; the only difference is that two strips are considered to form a grid. Again, only two people can do the searching walking through on separate strips and then will switch their strips for the more accuracy. It is a good method for large indoors and outdoors crime scenes.

The advantages of this method include:

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

The disadvantages include:

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.

4. Spiral Method

This is well suited for lager indoor and outdoor crime scene with less obstacles (like furniture etc.). The searcher will start either from the center of the room (outward) or from the periphery (inward) search as show in the images below. Also, two investigators can search together, one moving from the center towards the periphery and other one vice versa.

The advantages of this method include:

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

The disadvantages of this method include:

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.

5. Wheel Search Method

This method is only applicable to the lager outdoor scenes like fields, desert, or other such open areas. It is like the zonal method; however, the wheel is divided into various zones depending upon the size of the crime scene. Different individuals will be employed in separate zones and then switching their zone for more accuracy. The investigators or the searchers can begin from the epicenter moving towards their zones to complete the search, and then returning back to the epicenter for the discussion or collection procedures.

The advantages of this method include:

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

The disadvantages include:

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

6. Random Search Method

This is the most common method employed by the investigators, because of the feasibility at any location. No above-mentioned ruled to be followed for this method. It is also advisable to consider this method on complex crime scenes. 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.

The advantages of this method include:

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.

The disadvantages of this method include;

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.

7. 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:

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

The advantages of this method include:

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.

The disadvantages of this method are;

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.

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

The advantages include

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.

The disadvantages include:

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.

Conclusion

Collection of evidence must be done in a patient, comprehensive and non-destructive manner, within a reasonable period; and with a minimum of unnecessary movement at the crime scene. It is important that trained specialists collect and preserve evidence. The evidence collected first is usually that which is most fragile. Therefore, finger-prints should be lifted as a priority. Next, other fragile evidence, such as blood and other trace evidence should be collected. Evidence that has been collected must be protected and preserved until the case goes to court. Officers collecting evidence must preserve the chain of possession or chain of custody of all evidence collected. When possible, one police officer should serve as the evidence collector so that all evidence is collected in a uniform manner.