7 S's Of Crime Scene Investigation | Budding Forensic Expert

The 7 S's of Crime Scene Investigation | Budding Forensic Expert

The 7 S's of Crime Scene Investigation

1. Securing the Crime Scene

• Securing the scene is crucial to prevent contamination or loss of evidence until it is recorded and collected.
• The first responding officer (for example, police) is responsible for this step.

2. Securing the Witness

• Ensures every witness gives their own authentic testimony, uninfluenced by others.
• Key questions for witnesses:
  • When did the crime occur?
  • Who is the victim?
  • What did you see happen?
  • Where were you during the crime?
  • Can you identify the perpetrator?

3. Scanning the Scene

• Observe the area and identify primary (actual crime scene) and secondary (related locations) scenes.

4. Seeing the Scene

• Take photographs of the overall scene and close-ups of evidence, using different angles and distances—both with and without scales.

5. Sketching the Scene

• Create a permanent sketch showing the size and location of evidence, measured from fixed reference points.
• Indoors: reference doors, windows; outdoors: trees, vehicles, etc.

Crime Scene Sketch | Budding Forensic Expert

6. Searching for Evidence

• Apply systematic search methods:
  • Grid Search
  • Linear Search
  • Quadrant Search
  • Spiral Search

Searching Method | Budding Forensic Expert

7. Securing & Collecting Evidence

• Proper packaging, labeling, and sealing preserve evidence integrity.
• Use special packaging for different types (e.g., "druggist fold" for hair and fibers).

Chain of Custody

• Chain of custody is maintaining, documenting and handling evidence with a clear, detailed log.
• Tracks every handler or examiner during the investigation.

Steps in Chain of Custody

1. Evidence is packed, sealed and labeled.
2. Next handler opens the sealed bag at a new location.
3. Examines the evidence.
4. Repackages in the original packaging.
5. Seals in a new bag.
6. Signs both the bag and Chain of Custody log.

(This article is Prepared by Milik Ahmed and Guided by Ms. Anjali Malik, Assistant Professor, Forensic Science, Dept. Of Forensic Science, Sharda University)