Many at times when we hear there has been a fire episode, we often pray for the safety of citizens and wish for the fire to be put out as soon as possible. But when the designated authority goes in, it is revealed the fire was put intentionally, so now the whole episode becomes a crime scene.
This is what arson is; the act of setting fire to a property intentionally. Which becomes a criminal activity. The most common motive of committing arson is to conceal evidence in a property by setting everything on fire.
Fire Investigation Terms
Just like every other industry, the legal world of arson also has specific jargon. Here are some of the most common fire investigation terms and their meanings:
| Fire Investigation Term | Meaning |
| Accelerant | Fuel or oxidizer used to initiate or grow the fire |
| Area of origin | Part/location/structure where fire was originated |
| Backdraft | A deflagration resulting from the sudden introduction of air into a confined space containing oxygen deficient products of incomplete combustion. |
| Cause | The reason/cause of the fire or explosion |
| Combustible Liquid | Any liquid that has a closed-cup flash point at or above 37.8°C (100°F) |
| Combustion | Creates heat and light in a glow or flame |
| Conduction | Heat transfer to another body with direct contact |
| Convection | Heat transfer by circulation within gas or liquid |
| CFEI | Certified Fire and Explosion Investigator |
| CCFI | Canadian Certified Fire Investigator |
| CTT | Certified Technician/Technologist |
| EIT | Engineer in Training |
| Fire | The heat explosion by rapid oxidation |
| Fire Analysis | To determine the cause, development, and areas of the fire. |
| Fire Dynamics | The scientific research of heat and how it caused the fire |
| Fire Investigation | To determine further the point of origin, causes and development of fire in detail |
| Fire Scene Reconstruction | The process of recreating the physical scene during fire scene analysis through the removal of debris and the replacement of contents or structural elements in their pre-fire positions. |
| Flammable Liquid | A liquid that has a closed-cup flash point that is below 37.8°C (100°F) and a maximum vapor pressure of 2068 mm Hg (40 psia) at 37.8°C (100°F). |
| Flash Point of a Liquid | The lowest temperature of a liquid, as determined by specific laboratory tests, at which the liquid gives off vapors at a sufficient rate to support a momentary flame across its surface. |
| Fuel Load: | the total quantity of combustible contents of a building, space, or fire area, including interior finish and trim, expressed in heat units or the equivalent weight in wood. |
| Heat of Ignition | The heat energy that brings about ignition. |
| IAAI-CFI: | International Association of Arson Investigators – Certified Fire Investigator |
| Ignitable Liquid: | Any liquid that has the ability to catch fire |
| Material First Ignited | The fuel that is first set on fire by the heat of ignition; to be meaningful, both a type of material and a form of material should be identified. |
| Pyrolysis | A process in which material is decomposed, or broken down, into simpler molecular compounds by the effect of heat alone; pyrolysis often precedes combustion. |
| Radiation | Heat transfer by way of electromagnetic energy |
| Rekindle | A return to flaming combustion after apparent but incomplete extinguishment. |
| Spalling | Chipping or pitting of concrete or masonry surfaces. |
| Venting | The escape of smoke and heat through openings in a building. |
Arson Investigation Techniques
To investigate an arson, there are a couple of steps and techniques that are most important to determine the cause and point of origin of the fire. This is what investigators do when arson is suspected.
Step 1: Arriving at the crime scene
When investigators arrive at the crime scene, their first and foremost job is the safety of civilians and any people stuck inside the property. They need to make sure that people in need of care are receiving immediate medical attention and are transported safely away from the scene.
Next, they observe the surroundings. The location of the fire, witnesses and victims, bystanders, vehicles arriving and leaving the crime scene. Who was the first public safety personnel to attend to the crime scene, fire suspension techniques used etc.
While the investigators arrive at the crime scene, they are making mental notes of everything that is available and seen. Then they preserve the fire scene by establishing security and control, evacuating all citizens and unauthorized persons away from the scene.
Step 2: Evaluation
The next step is to start evaluating the crime scene, call first responders, determine the point of origin, see what has been damaged and what is still somewhat intact. Request for a larger team if more people are required, interview and talk with witnesses and victims of the fire.
The investigator then observes the crime scene closely, was there a break and enter, what is the condition of doors and windows, are the cupboards and cabinets empty, how many people were living in the house/property, if their basic belongings are gone, it could be assumed that the owner knew about the fire that it was going to happen. If valuables are gone, it could be a theft before the house was set on fire.
Step 3: Recording and Documenting
This is the step where photographs are taken, evidence is gathered and notes are made. Everything about the scene, even the non-significant areas are photographed and then reviewed later by forensics. The investigator or no one from the team is allowed to move items or touch them barehand because they could mess with the evidence.
Evidence is carefully collected and put into forensic approved containers and polyester bags, it is done so very carefully to avoid the contamination of the evidence. Each package is carefully labelled and then transported to labs and forensic departments for further investigation, but make sure with every evidence the chain of custody SHOULD be maintained.
After necessary measures are taken to evaluate, document and transport all evidence safely, the investigator can now release the scene and properly give out precautions to the receiving party. These are some things typically that arson investigators look for in a crime scene.
How long does Fire Investigation take?
A small fire episode can take around a week, but a major arson or fire investigation can take more- up to 2-3 weeks. Usually it doesn’t take more than that. During this time the cause, point of origin and suspected arsonists are listed down, and with time the investigators are to bring witnesses and suspects when and if the case is brought to court.
Forensic Arson Investigation
Forensic investigation is the medical and scientific evaluation of an arson; the evidence is sent to labs and scrutinized to figure out more about the crime. Science is used with evidence to establish facts about a certain criminal activity, and in an arson case it could also lead to the criminal itself.
A complete forensic evaluation may take 15 to 35 hours to complete, depending upon the number of evidence and media files.
Conclusion
Typically, arson investigators look for evidence and cause of the arson on the targeted property/house. The investigation team is all set to record and document the crime scene for later examination and after that the crime is fully investigated.
Who were the suspects, what caused the fire, what time was it caused, has the insurance company been notified, are there any fire victims etc- so many questions and all of these are answered based on facts established after scrutinizing the evidence.
