What are the 7 S’s of crime scene investigation? This question is at the heart of any successful crime scene investigation. By following these seven steps, investigators can ensure that they are collecting all of the evidence necessary to solve a crime.
These steps are essential for any crime scene investigator to follow in order to ensure a thorough and accurate investigation.
The 7 S’s of crime scene investigation are: secure the scene, survey the scene, search the scene, seize evidence, sketch the scene, photograph the scene, and special considerations.
1. Secure the Scene
Securing the crime scene is crucial to preserve the integrity of evidence and ensure the safety of investigators and others. It involves establishing a perimeter to control access, preventing contamination, and minimizing the risk of destruction or alteration of evidence.
Methods for securing the crime scene include:
- Establishing a perimeter with physical barriers (e.g., tape, ropes)
- Restricting access to authorized personnel only
- Controlling movement within the scene to prevent trampling or disturbance of evidence
- Documenting the initial scene before any movement or alteration
Potential hazards that must be addressed during scene securing include:
- Biological hazards (e.g., blood, bodily fluids)
- Chemical hazards (e.g., fumes, gases)
- Physical hazards (e.g., broken glass, sharp objects)
- Electrical hazards
2. Survey the Scene
Surveying the crime scene involves a systematic examination of the area to identify and document potential evidence. It is a preliminary step that helps investigators plan their search strategy and determine the resources needed.
Steps involved in surveying the crime scene include:
- Walking through the scene to observe the overall layout and identify areas of interest
- Noting the location and condition of any objects, stains, or other potential evidence
- Observing the surroundings for any relevant information (e.g., footprints, tire tracks)
Techniques used to document the scene include:
- Taking notes and sketches
- Using photography to capture the overall scene and specific details
- Creating a video recording to provide a comprehensive overview
3. Search the Scene
Searching the crime scene is a systematic process of examining the area for evidence. It involves using various methods to locate and recover items that may be relevant to the investigation.
Different search methods used in crime scene investigation include:
- Strip search: A systematic search of an area in a straight line, covering a narrow strip
- Grid search: A search of an area by dividing it into a grid and searching each section systematically
- Spiral search: A search of an area by moving in a spiral pattern, starting from the outside and working inward
- Zone search: A search of an area by dividing it into zones and assigning each zone to a different team
The grid search technique is a commonly used method that involves dividing the scene into smaller sections and searching each section thoroughly. It is a systematic and efficient way to ensure that all areas are covered.
Proper documentation is crucial during the search process. Investigators must record the location and description of any evidence found, as well as the search method used and the time spent searching each area.
4. Seize Evidence
Evidence collection and preservation are essential to ensure that the evidence is admissible in court and can be used to reconstruct the crime. It involves properly collecting, handling, and storing evidence to maintain its integrity.
Principles of evidence collection and preservation include:
- Collecting only relevant evidence
- Minimizing contamination and alteration
- Properly packaging and labeling evidence
- Maintaining a chain of custody to document the handling of evidence
Different types of evidence that can be collected include:
- Physical evidence (e.g., weapons, clothing, fingerprints)
- Biological evidence (e.g., blood, DNA)
- Digital evidence (e.g., electronic devices, computer data)
- Documentary evidence (e.g., letters, receipts)
Proper handling and storage of evidence is crucial to preserve its integrity. Evidence should be packaged in a way that prevents contamination or damage, and it should be stored in a secure location with controlled temperature and humidity.
5. Sketch the Scene
Creating a detailed sketch of the crime scene is a crucial step in crime scene investigation. It provides a permanent record of the scene layout, the location of evidence, and other relevant details.
Techniques used to create an accurate sketch include:
- Measuring the scene and its features
- Using a scale to ensure the accuracy of the sketch
- Noting the location and condition of all relevant objects, including furniture, appliances, and windows
The sketch should be drawn to scale and include a legend to explain the symbols and abbreviations used. It should be clear and easy to understand, providing a comprehensive overview of the crime scene.
6. Photograph the Scene
Crime scene photography is a vital part of the investigation process. It provides a visual record of the scene, capturing details that may not be visible to the naked eye or may change over time.
Principles of crime scene photography include:
- Taking photographs from different angles and distances
- Using a scale to show the size of objects
- Capturing close-ups of important details
- Documenting the scene before and after any changes are made
Different types of photography used in crime scene investigation include:
- Overview photographs: Provide a general view of the scene
- Medium-range photographs: Capture details of specific areas or objects
- Close-up photographs: Show fine details and evidence
Photography can be used to document the location of evidence, injuries, and other important details. It is a powerful tool that can help investigators reconstruct the crime and present evidence in court.
7. Special Considerations: What Are The 7 S’s Of Crime Scene Investigation
In addition to the standard procedures, crime scene investigation may involve special considerations depending on the nature of the crime and the environment.
Challenges of investigating outdoor crime scenes include:
- Exposure to weather conditions
- Larger and more complex scenes
- Difficulty in preserving evidence
Working with experts in specific fields may be necessary to properly investigate certain types of crimes. For example, in cases involving arson, a fire investigator may be consulted to determine the origin and cause of the fire.
Question Bank
What is the first step in crime scene investigation?
The first step in crime scene investigation is to secure the scene.
What is the purpose of sketching a crime scene?
The purpose of sketching a crime scene is to create a permanent record of the scene.
What are the different types of evidence that can be collected at a crime scene?
The different types of evidence that can be collected at a crime scene include physical evidence, biological evidence, and trace evidence.
