Search Methods Used in Crime Scene Investigation


A crime scene is a location where a crime has taken place. The goal of a crime scene investigation (CSI) is to examine the entire scene and identify the perpetrator based on the evidence obtained at the crime scene. Crime scene investigators are the people that are involved in this procedure.

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The crime scene should be thoroughly inspected. There are several strategies for exploring the scene for evidence rationally and practically. The size and nature of crime scenes determine which search procedures are used. The search must cover all points of access, escape, and retreat that the culprit may have used.

police investigating the crime scene
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Crime Scene Search Methods

Following the completion of the documentation, the crime scene investigation team begins searching the whole protected area for evidence. If there is a dead corpse on the scene, it is initially investigated from every angle. The dead person’s fingerprint is taken down, as well as his or her body temperature. Following that, the entire region is inspected in five different ways:

  • Link Method
  • Line / Strip Search Pattern
  • Grid Search Pattern
  • Spiral Search Pattern
  • Wheel / Ray Search Pattern
  • Quadrant / Zone Search Pattern
  • Random Search Method

Link Method

This Method is based upon the linkage theory, also most common and productive method. In this method one type of evidence leads to another item. This is logical, and systematic method which works with large and small, indoor or outdoor scenes

Link Method
Link Method

Line or Strip Method

In this searching methods, investigators begin at one end of the area and move straight to the other. The strategy is beneficial when the crime scene borders are properly defined, as the limits show where the crime scene begins and ends. One or two detectives should thoroughly inspect the area to ensure no evidence is left behind.

Line Method
Line Method

Grid Method

Modified, double line search; effective method but time-consuming

It’s similar to the strip method, with the exception that two strips are regarded to constitute a grid. Only two individuals can accomplish the searches by going through different strips and then switching strips for more precision. It’s a fantastic strategy for vast crime scenes, both indoors and out.

Grid Method
Grid Method

Zone Method

Best used on scenes with defined zones or areas; effective in houses or buildings with rooms; teams are assigned small zones for searching; often combined with other methods; good for search warrants

The crime scene is essentially split into several zones using this strategy. The number of zones is determined by the crime scene’s size and complexity. This technique may be used to investigate both interior and outdoor crime sites. Different individuals will be assigned to different zones, and they will search their zones meticulously for evidence using both traditional methods and advanced tools. After they’ve completed their searches in their individual zones, the zones will be swapped to ensure accuracy and to double-check for any missing objects. This strategy is ineffective in crowded and complicated crime scenes like elevators, or stairwells.

zone method
Zone Method

Wheel or Ray Method

Used for special situations; has a limited application; best used on small, circular crime scenes

This approach is only suitable for larger outside sceneries such as fields, deserts, or other vast spaces. It’s similar to the zonal approach, except the wheel is divided into different zones based on the size of the crime scene. The wheel search pattern involves numerous people looking in a straight line from the scene’s center or focal point to the limits, or from the boundaries to the scene’s focal point.

Wheel Method
Wheel Method

Spiral Method

Inward or outward spirals; best used on crime scenes without physical barriers (e.g., open water); requires the ability to trace a regular pattern with fixed diameters; has limited application.

From the boundaries to the center of the crime scene, or from the focal point of the scene, the investigator advances inward in a spiral with increasing circumference until the whole crime scene is covered. In fact, two investigators can work together to search, one moving from the center to the perimeter and the other vice versa. Because the searcher proceeds from the region with the least evidence to the area with the most evidence, a spiral search from perimeter to center is beneficial. In most bomb blast incidents, the spiral method is used.

  • Inward Spiral Search

Using the spiral movement strategy, the CSI team begins their investigation at the edges and works inward.

  • Outward Spiral Search

In this strategy, the CSI team begins its investigation in the center of the scene and works its way outward in a spiral pattern.

Spiral Method
Spiral Method

Random Search Method

It is a search technique that uses no special pattern, and the investigator can search for evidence randomly as the name implies. Due to its adaptability to any setting, this is the method that investigators use the most frequently.

The investigating officer is free to begin looking for evidence in whatever way they see appropriate given the crime scene. It’s also a good idea to take this approach into account for complex crime scenes.

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