Crime scene strategy

The crime scene strategy will be case dependent, but the basic principles for the scene assessment will be the same.

The information will be received and the initial response will be to sent a police officer to the scene. They will be known as the first attending officer (FAO). Their responsibility will be to:

Preserve life

Administer first aid or call for ambulance assistance.

Establish cordons

Preserve and secure the scene to minimise contamination and disturbance of evidence. This includes setting up cordons. It is likely that there will be inner and outer cordons. The outer cordon surrounds the whole scene whereas inner cordons protect specific areas within the scene.

Preserve evidence

If there are any obvious evidence types eg a potential weapon, then the FAO will protect this by any means possible. For example, if it was raining, then they would cover the weapon with anything that they could find ie a bin lid.

Establish the common approach path

The entrance and exit points of all involved (perpetrators, victims etc) should be identified. A route should then be created for the investigation team that is away from these areas to limit disturbance of the scene, known as the common approach path.

Initiate the crime scene log

This will be created to maintain the integrity of the scene by making sure that only essential people enter the scene. It is a record of the names and times people enter and leave the scene.

Consider health and safety

The safety and wellbeing of all those attending the scene is of paramount importance. Hazards could be physical (eg sharps or dangerous individuals), biological (eg blood or other body fluids) or chemical (eg found in a clandestine drug laboratory or the chemicals used at the scene).

After all of these steps have been considered, there will be a walk-through in order to identify areas of interest and to create the forensic strategy. The forensic strategy will include: the systematic search strategy to be used (spiral, grid, strip/line or quadrant/zone), methods and order of evidence recovery, identification of the experts needed to attend the scene, such as a Blood Pattern Analyst, and identifying what tools are required (lighting, packaging etc).

Evidence must then be collected and packaged correctly. This will then be transported either for storage or taken to a scientific laboratory for analysis. It is important that throughout this process the chain of custody is maintained.

Systematic search strategies for evidence

  • Spiral search method
  • Grid method (with a clear start and end point)
  • Strip or line search
  • Quadrant or zone search

The diagram shows the four search strategies as line diagrams

Share this article:

This article is from the free online course:

The Science Behind Forensic Science

King's College London

Get a taste of this course

Find out what this course is like by previewing some of the course steps before you join: