Forensic Fire Investigations

We examine the scene and gather information to establish the origin, cause and circumstances of an incident.

The primary purposes of a fire investigation is to establish the origin (seat) of the fire, determine the likely cause, and thus conclude whether the incident was accidental, natural or deliberate. It is vital to establish the cause to ensure similar events do not occur (in the case of natural or accidental) or to allow a legal investigation to be conducted (in the case of deliberate fires).

Fire Site Safety

The initial concern with regards to a fire incident scene is safety. Such a scene has an increased risk factor with possible hazards including heated materials, structural collapse, damaged electricity and gas mains, debris, asbestos, dangerous combustion products and other toxic substances. A dynamic risk assessment should be conducted, the scene must be declared safe and all individuals entering the scene should wear appropriate protective clothing such as hardhats, fire-resistant overalls, steel-capped boots, and thick gloves and, in some cases, a face mask. Supplies of gas and electricity should be switched off before the investigation begins.

Witnesses of a Fire

Information regarding a fire can be obtained from witnesses. Witnesses may be able to provide details of the premises prior to the fire in addition to details of the fire itself, such as suspicious activity or apparent fire spread and smoke colour. Onlookers may even have taken photographs or video recordings of the incident on their mobile phones or cameras. The owner of the building/area may be able to detail the contents and layout of the building as well as any other potentially pertinent facts. However it should always be taken into consideration that civilian witnesses may be unreliable and could even have been involved in the fire incident. Emergency service personnel, such as police and fire fighters, are considerably more reliable as witnesses. Fire fighters in particular may be able to provide useful information on the possible origin of the fire and any unusual conditions. Fire fighters should also be interviewed to identify any disturbances made to the scene during fire-fighting efforts. Ideally eyewitnesses should be interviewed by an objective individual with experience in interviewing in such a way that the information they provide is not influenced.

Scene Examination

A fire incident should be treated as a crime scene in that the area should be strictly controlled by a cordon to preserve evidence and allow access to authorised personnel only, with the scene and evidence being fully documented. A plan of the premises should be produced where possible to include the locations of objects, though it must be taken into consideration that disturbance may have been caused during fire-fighting efforts.

Establishing the Origin of a Fire

A vital aspect of the forensic fire investigation is to establish the point of origin of the fire, also known as the seat of fire. There are numerous indicators that can be used to determine the possible origin. The region in which a fire started will generally burn for a longer amount of time, thus will be an area with the worst damage. Fires tend to burn upwards, therefore the seat of the fire is likely to be found at a lower point of burn damage. However this is not always reliable as fires can spread downwards, particularly in the presence of certain fuel sources.

Establishing the Cause of a Fire

Determining the cause of the fire is often greatly aided by locating the seat of fire, at which point investigators can identify characteristics or artefacts associated with ignition. The investigator will aim to establish whether the cause of the fire was accidental, natural, deliberate or undetermined. Accidental fires generally involve no malicious human contact, with examples including the malfunction of an electrical appliance or an unattended candle. Natural fires include "acts of God", such as lightning strikes. Deliberate fires are those ignited purposely by individuals, often with malicious intent, in an act known as arson. Finally, if the cause of the fire cannot be ascertained due to lack of evidence, it may be classed as undetermined.


There are numerous indications of the deliberate ignition of a fire, also known as arson. Cases of arson are of particular importance to the forensic investigator, and such incidents may arise for a variety of reasons, such as insurance fraud, terrorism, in attempts to harm a person or their property, mental health problems, or to conceal a previous crime.