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Compromised investigations and scene preservation: Fires

Hazard Knowledge

See National Operational Guidance: Operations- Compromised investigations and scene preservation

At any time during and after an operational incident there may be the need to carry out some form of investigation. This may be because of an adverse health and safety event, suspected criminal activity or a statutory body carrying out their duties. The need to preserve evidence and secure a scene when responding to a fire is a concern as operational activities and the fire’s development may destroy evidence that is crucial to the effective investigation of an incident.

Evidence can take many forms, from broken glass at the point of entry to twisted or scrunched paper used as an initiating fuel papers and/or flammable material piled in the scene, petrol cans or other containers with strong odours or fingerprints left on items damaged at, or brought into, a fire scene.

In some instances, fire may be used specifically to destroy evidence; for example, forensic evidence, vehicles, machinery, documentation or stock in commercial premises. The way in which the fire was started or the presence of multiple seats of fire be potential evidence.

Fingerprints can withstand the effects of indirect heat and water contamination; fingerprints will remain on objects such as bottles, containers and papers even when covered with soot. Authorised personnel entering the fire scene should therefore avoid touching or moving items with bare hands. Items should not be moved or handled until a police crime scene investigator or fire investigator has assessed these items in situ.

Damping down operations can damage potential evidence at a fire scene. Damping down operations should therefore be managed and controlled to address hot spots using the least physically intrusive methods possible to cool specific areas. For example, a hose reel, with the branch set to spray, using the lowest pressure possible, should be used to gently cool the targeted hot spot.