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Compromised investigations: Poor scene preservation

Hazard Knowledge

It is important to consider the need to preserve the scene of the incident for investigation. Actions taken at all stages of an incident may affect the preservation of evidence.

Failing to properly secure and manage a scene may allow contamination of the scene, with a resultant loss of evidence. If scenes are not properly managed, this can distort initial findings and prolong subsequent efforts to identify the cause of the incident, and potential offenders.

Investigation of an incident is a complex and specialist task; it is important that the scene is preserved as completely as possible and accurate records kept following the conclusion of the incident. They may be required as evidence in legal proceedings.

The need to investigate should not affect bringing an incident to a safe and satisfactory conclusion, nor interfere with incident objectives and priorities. During an incident, there may be an opportunity to scale down incidents and allow investigators into safe areas, but this should not affect ongoing operations and scene safety should remain a priority. Nominating safe paths to and from the scene will assist in protecting evidence and the safety of investigators.

Allowing evidence to be lost or contaminated, or keeping incorrect or incomplete records of actions, may affect an investigation with serious consequences. Understanding the reasons for investigation helps to establish why failing to preserve a scene can be hazardous. Investigations are required to:

  • Help prevent similar events from occurring, by identifying trends
  • Enable better targeting of enforcement and advice
  • Assist in the prosecution of offenders
  • Assist with legal proceedings
  • Contribute to national statistics through accurate reporting on the incident recording system (IRS)
  • Assist with advising and educating young people
  • Assess the effect of fire and rescue service intervention
  • Understand the cause of the incident
  • Understand the functioning of safety features

Any fire and rescue service action that impedes or prevents investigation affects this process. Therefore, it is the responsibility of all responders to support the investigative process which, if successful, may reduce the frequency or severity of incidents, and improve intervention.

Investigating a scene is inherently hazardous. Every person involved in the activity should aim to minimise the risk involved, while performing as full an investigation as possible. Even post-incident, incident commanders should consider the following factors to minimise risk:

  • Identify the hazards, assess and record the risks at the scene and establish the appropriate control measures, including:
    • Personal protective equipment (PPE)
    • Respiratory protective equipment (RPE)
  • Identify the type, location, extent and circumstances of the incident
  • Identify and evaluate available information
  • Identify which specialists and other agencies need to be involved

To aid this process, a risk assessment must be carried out by the investigating officer during investigations.

Contamination of the scene

Contamination transfer can occur if ‘foreign objects’ are brought inside cordon areas. These objects can include:

  • Personal protective equipment (PPE)
  • Gloves
  • Drink or food packaging
  • Cigarettes
  • First aid supplies

Any contaminated transfer creates false evidence that could waste significant time and resources to identify, recover and process forensically during the key phase of an investigation.

DNA evidence is robust and can withstand heat, soot contamination and water. However, in many cases, it may not be immediately apparent where the DNA evidence has come from. Any blood injuries to an emergency responder that occur within the inner cordon should be noted and brought to the attention of the relevant agency, particularly in a police-led investigation.

Loss of evidence

Evidence at the scene may be lost or compromised by events, including:

  • Damage being caused by exposure to the elements
  • Disturbance by material being moved from its original position, including by:
    • People involved in the incident
    • Emergency responders
  • Disturbance by items being taken into it
  • Disturbance by material being removed from it
  • Cross-contamination by transference between scenes
  • Vehicle disturbance
  • Animal disturbance
  • Microbiological activity causing decay to material