The Seven S's Of Crime Scene Investigation

The Seven S's of Crime Scene Investigation: A Comprehensive Guide

Crime scene investigation is a meticulous and methodical process, crucial for solving crimes and bringing justice to victims. To ensure accuracy and avoid compromising evidence, investigators follow a standardized procedure often summarized by the "Seven S's": Securing the Scene, Separating the Witnesses, Scanning the Scene, Seeing the Scene, Sketching the Scene, Searching for Evidence, and Securing and Collecting Evidence. This guide delves into each step, providing a detailed understanding of the complexities and importance of each.

1. Securing the Scene: The Foundation of a Successful Investigation

The very first step, and arguably the most crucial, is securing the scene. This involves establishing a perimeter to prevent unauthorized access and contamination. The safety and integrity of the crime scene are paramount. This initial action prevents the loss, destruction, or contamination of crucial evidence. Before any investigation begins, the first responders—often police officers—must establish a secure perimeter, controlling access and preventing anyone from entering or leaving the scene without authorization.

Key Actions in Securing the Scene:

• Establishing a perimeter: This involves marking a clear boundary around the scene, using caution tape, cones, or other physical barriers. The size of the perimeter depends on the nature of the crime and the potential extent of evidence dispersal. Larger, more complex scenes may necessitate a larger perimeter and multiple control points.
• Controlling access: Only authorized personnel—investigators, forensic specialists, and essential support staff—should be allowed within the perimeter. A logbook should be maintained to record the entry and exit of all individuals. This detailed record is essential for maintaining chain of custody and avoiding any allegations of tampering.
• Protecting the scene from contamination: Preventing contamination is crucial. Investigators should wear protective gear, including gloves, masks, and shoe covers, to minimize the risk of transferring or introducing extraneous materials. Appropriate signage should warn against touching or disturbing anything within the crime scene.

Failure to secure the scene properly can lead to:

• Loss of evidence: Evidence can be easily lost, damaged, or destroyed if the scene isn't properly secured. This can severely hinder or even compromise the investigation.
• Contamination of evidence: Uncontrolled access can lead to the contamination of evidence, making it unusable in court. This can significantly weaken or even invalidate a case.
• Compromised investigation: A compromised scene can undermine the entire investigation, potentially leading to a wrongful conviction or the release of a guilty party.

2. Separating the Witnesses: Preventing Collusion and Ensuring Accurate Testimony

After securing the scene, the next step is separating the witnesses. This crucial step prevents witnesses from collaborating and influencing each other's accounts of the events. Individual statements gathered independently are more reliable and less susceptible to bias or misinformation.

Importance of Witness Separation:

• Preventing collusion: Witnesses who discuss the event together might inadvertently influence each other's memories or create a shared, possibly inaccurate, narrative. Separation prevents the fabrication or alteration of testimony.
• Ensuring accurate accounts: Individual accounts, taken separately, are more likely to be unbiased and reflect individual perceptions of the event. Comparing and contrasting these individual accounts helps investigators determine inconsistencies and identify possible inaccuracies.
• Identifying inconsistencies: Discrepancies between witness testimonies can highlight areas requiring further investigation and assist in pinpointing potential suspects.

Each witness should be interviewed separately and asked to provide a detailed account of the events they witnessed. Their statements should be recorded, either written or via audio/video recording, to ensure accuracy and preserve their testimony for future reference.

3. Scanning the Scene: A Preliminary Overview of the Crime Scene

Scanning the scene is a preliminary survey of the crime scene to establish an overall understanding of the layout and potential areas of interest. This visual assessment provides the initial context for the investigation. It's a quick but crucial overview that directs subsequent, more detailed examinations.

The Importance of Scanning:

• Initial assessment: This provides an initial understanding of the scene's size, layout, and potential areas of evidence. It allows investigators to plan their strategy for a more detailed and methodical search.
• Identifying key areas: The scan helps identify potentially significant areas, like points of entry or exit, areas of struggle, or locations of specific evidence.
• Planning the search: A preliminary scan informs the subsequent search strategy, ensuring that evidence is found efficiently and systematically. This planned approach is crucial to avoid overlooking important evidence.

This initial scan is typically done from a distance to avoid disturbing the scene before the more detailed stages of the investigation. Photographing the scene from various angles at this stage forms the basis for subsequent documentation.

4. Seeing the Scene: Detailed Examination and Photography

Seeing the scene involves a detailed examination of the crime scene, focusing on identifying, documenting, and preserving all potential evidence. This involves a thorough visual inspection and the systematic recording of observations through photography and videography.

Key Aspects of Seeing the Scene:

• Detailed photography: High-quality photographs should be taken from various angles and distances, providing a comprehensive visual record of the crime scene and the location of all potential evidence. Close-up shots are crucial to capture details of smaller items.
• Videography: Videography complements photography by providing a dynamic record of the scene, including its context and the investigator's movements. This can be particularly useful for demonstrating spatial relationships between objects and evidence.
• Notes and observations: Detailed notes should be made, recording all observations, including the location and condition of evidence, environmental factors, and anything else that could be relevant. This meticulous recording allows for a comprehensive reconstruction of the crime scene.

This detailed documentation ensures that the crime scene can be reconstructed and analyzed even after the physical scene has been processed. It forms a crucial part of the evidence presented in court.

5. Sketching the Scene: A Visual Representation of Spatial Relationships

Sketching the scene provides a visual representation of the crime scene, indicating the location of evidence and other relevant features. This diagrammatic representation complements photographic and video evidence, providing a clear understanding of spatial relationships.

The Value of Sketching:

• Spatial relationships: Sketches accurately depict the location of evidence relative to other objects and features in the crime scene. This is crucial for understanding the sequence of events and the potential movements of individuals.
• Perspective and scale: Sketches provide perspective and scale, offering a clearer understanding of the size and arrangement of items within the crime scene. Accurate measurements should be incorporated into the sketch.
• Courtroom presentation: Sketches are an effective visual aid for presenting evidence in court, helping jurors understand the layout and circumstances of the crime scene.

Sketches can be rough, initial sketches made at the scene, or more detailed, finalized versions created later. Regardless, accuracy and clarity are essential.

6. Searching for Evidence: A Systematic and Thorough Approach

Searching for evidence is a systematic and thorough process of locating and documenting all potential evidence at the crime scene. Different search methods may be employed depending on the nature of the crime scene and the type of evidence being sought.

Common Search Methods:

• Grid search: This method involves dividing the crime scene into a grid pattern and systematically searching each section. This ensures a thorough and comprehensive search, minimizing the risk of missing evidence.
• Spiral search: A spiral search involves moving inward or outward from a central point, following a spiral pattern. This is useful in smaller, less complex scenes.
• Linear search: This involves establishing a line of searchers who move systematically across the scene, covering the area in a linear fashion. This method is suitable for large, open areas.
• Zone search: This method involves dividing the crime scene into zones and assigning different search teams to each zone. This is useful in larger, more complex scenes where multiple teams can work simultaneously.

The choice of search method depends on several factors, including the size and complexity of the scene, the terrain, and the type of evidence being sought.

7. Securing and Collecting Evidence: Maintaining the Chain of Custody

Securing and collecting evidence is the final step of the Seven S's and is crucial to maintain the integrity of the evidence. This involves properly packaging, labeling, and storing evidence to prevent contamination and ensure its admissibility in court. Maintaining the chain of custody is vital—a meticulously documented record of every individual who handled the evidence, from its discovery to its presentation in court.

Key Considerations in Evidence Handling:

• Proper packaging: Evidence must be packaged appropriately to prevent contamination and damage. Different types of evidence require different types of packaging. Biological evidence, for instance, requires specific containers to prevent degradation.
• Labeling: Each piece of evidence must be clearly labeled with identifying information, including the date, time, location, case number, and the name of the individual who collected it.
• Chain of custody: A detailed record of every individual who handled the evidence, including the date and time of each transfer, must be maintained. This record ensures the integrity of the evidence and prevents any allegations of tampering.
• Storage: Evidence must be stored in a secure location to prevent contamination and damage. Temperature and humidity-controlled storage is often necessary to preserve certain types of evidence.

Properly securing and collecting evidence is crucial for the success of any criminal investigation. Failure to do so can lead to the dismissal of evidence, compromising the entire case.

The Seven S's of crime scene investigation provide a framework for a methodical and thorough approach to processing a crime scene. Each step is crucial, and adherence to these procedures ensures the integrity of the investigation, maximizes the chances of successfully solving the crime, and helps bring justice to the victims. The importance of meticulousness, attention to detail, and the preservation of evidence cannot be overstated.