How to Determine If a Fire Is Arson

Arson is regarded as one of the easiest crimes to perpetrate and the most challenging to identify and verify. It requires the work of skilled fire and arson investigators sifting through rubble and debris to determine if a fire was arson. While it takes year of experience to spot the signs of an incendiary fire, there are basic guidelines every investigator follows. Read on to learn how to determine if a fire is arson.

Instructions

Difficulty: Challenging

Things You’ll Need:

• Knowledge of the properties of fire
• Knowledge of spontaneous combustion
• Training in cause and origin determination
• Training in crime scene investigation
• Investigative skills
• Accelerant detection dog
• Laboratory access
• Internet access

1. Look for clues that the fire was set intentionally and should be considered arson. Canvas the entire fire scene beginning at the area suffering the least amount of damage. Also check the structure's exterior for signs of forced entry, footprints, gasoline containers and rags.
2. Eliminate as many accidental causes as possible. The obvious ones include faulty electrical wiring, cigarettes left unattended, malfunctioning appliances and sparks from fireplaces or wood stoves.
3. Determine the area of origin. Multiple sites indicate the fire was intentionally set. Identify any structural deformities caused by the fire, such as V-patterns on the walls, smoke patterns or charring. Search for remnants of combustible materials that may have been used to start the fire.
4. Collect evidence, both trace and physical, from the fire scene to determine the fire's origin, identify accelerants, and connect an arsonist to the scene. Trace evidence is anything that can link the arsonist to the fire, including hair, traces of blood, clothing or fibers.
5. Use your sense of smell to detect the odor of catalysts, such as paint, fuel, turpentine, chemical solvents or alcohol. Collect samples of any remaining accelerants and send them to the laboratory for analysis.
6. Examine the fire scene for sources of ignition, such as matches, cigarette lighters, chemicals, fireplaces, chimneys and utility lines.
7. Verify that all electrical appliances are in proper working order, thereby eliminating them as possible causes.
8. Use an accelerant detection dog to help determine if a fire is arson. Because of their acute sense of smell, these dogs are able to identify minute amounts of liquid accelerants at a fire scene and on the clothes of onlookers and/or possible suspects.
9. Interview any witnesses and first responding firemen and police for possible leads.

Tips & Warnings

• Fire investigators should always work in pairs.
• Search the Internet for information on obtaining an accelerant detection dog.
• Check to see if other arson fires have been reported in the area.
• The best place to look for residuals is where the burned and not burned sections of the structure come together.