Securing the scene and preserving evidence should commence immediately if doing so does not affect safety or the successful conclusion of an incident.
Incident commanders should achieve scene security and evidence preservation by establishing and maintaining cordon controls.
Incident commanders should use cordons to keep the public out and maintain control within the inner cordon. A cordon should start as large as practicable until such a time as resources can be released from a scene and the size of the cordon reduced. The police crime scene investigators may search the inner cordon to ensure that any potential evidence is recovered. Other agencies may wish the cordon to be of a specific configuration; incident commanders should liaise with them and balance safety concerns with the needs of investigating agencies.
Only authorised personnel should enter the scene and a clear common approach path must be used for all authorised personnel to protect physical evidence and prevent cross-contamination.
If there are any doubts about the cause, requests (after the operational phase of the incident has been concluded) to allow occupiers or others to enter a property or access a vehicle should be considered carefully. If allowed, the person must be accompanied and supervised and the actions/people/locations recorded.
Where necessary windows and apertures that give a vantage point to see into the scene should be covered to prevent direct observation.
The decision to leave identified physical evidence at the scene should be carefully considered. If it is essential to move anything, a record should be kept with reasons/implications explained. Care is needed where insurance claims will be made as the property may transfer ownership to the insurance company.
Personnel need to be aware that scene preservation will be necessary to enable other organisations to investigate an incident fully. Fire and rescue services should ensure that only personnel required to deal with the incident access the site and that any necessary movement of casualties, objects and wreckage is minimised.
Once rescue and firefighting operations are complete, the responsibility for the security of an incident, property, contents and personal effects will be that of the police or the statutory investigation team. All personnel should consider how their actions may affect any subsequent investigation and identify and prioritise evidence that may deteriorate.
Early liaison to establish the requirements of the statutory investigation team is required. However, the control of the scene should not interfere with any lifesaving activities or fire and rescue service statutory duties.
It is important to control the number of people allowed on the incident site so that evidence such as personal effects are not disturbed, or are disturbed as little as possible. When the situation permits, there should be a careful withdrawal of all non-essential personnel and equipment. Where casualties or bodies are moved, great care should be taken to ensure that any item that is adjacent is recorded or moved with the casualty or body.
The police may be required to take control of cordons after they are established and maintain scene logs.