Investigating suspicious fire claims
An established fire investigator can utilize a variety of tools depending on the complexity of the scene.
Determining the origin and cause of a fire requires adherence to the scientific process as well as the painstaking collection and analysis of evidence. Details that point to the possibility of arson introduce a criminal and emotional element to the investigation that may seem daunting, but keeping a cool head and following the scientific method allows you to draw an unbiased, evidence-based conclusion.
Remember that confirmation bias can derail an investigation. Just because you may suspect that the fire was deliberately or maliciously set, it’s important to engage a certified, experienced fire investigator to complete an inspection and determine the cause of the fire. The National Fire Protection Association (NFPA) 921 provides guidance for the methodology used to conduct an unbiased investigation. This document requires the seven steps of the scientific method to be used to determine the origin and cause of all fires.
- Recognize the need: A fire has occurred and the origin is unknown.
- Define the problem: Determine the origin of the fire or explosion.
- Collect the data: Gather the basic site data; determine the pre-fire and post-fire conditions; evacuate, examine and reconstruct the scene; collect witness statements; obtain fire department information, alarm, detector and security data.
- Analyze the data: Complete a fire pattern analysis, identify ventilation-generated patterns, conduct a flame and vector analysis, finish an origin matrix analysis, complete depth of char and calcination surveys, finalize arc mapping, complete event sequencing, consider fire dynamics, and study building construction and occupancy.
- Develop hypotheses: Formulate an initial origin hypothesis, determine a working origin hypothesis and consider alternative hypotheses.
- Test the hypotheses: Determine whether there is a competent ignition source in the area of origin, whether the origin explains the data collected, whether all contradictions are resolved and whether an alternative origin explains the data equally well.
- Select final hypothesis: Determine the area of origin and the point of origin, or that there is insufficient information to determine the origin.
The NFPA defines arson as an incendiary fire “intentionally ignited in an area under circumstances where and when there should not be a fire.” Because arson is a crime, adherence to the scientific process is of the utmost importance to your investigation. Make sure you engage a reputable and fully licensed fire investigator to ensure that your investigation is completed professionally and conclusively.
The fire investigator’s role
Once a fire investigator is engaged, communicate with him or her promptly and clearly. The fire investigator will complete interviews to obtain background information about the structure, equipment, or vehicle where the fire loss occurred and any firsthand information about the discovery of the fire. Typical interviewees at this stage include the owner, occupant or driver/operator, the tenant, any witnesses, the person who discovered the fire, the person who called 911 to report the fire, fire department personnel, public fire investigators and law enforcement. Based on the information gathered during this stage, other people may be contacted for an interview.
Upon arriving at the fire scene, the fire investigator will survey the loss to ensure safe conditions for an inspection. They will photograph the exterior post-fire conditions and document all damage. Key indicators of a possible arson here include signs of forced entry not caused by the fire department or signs of blocked entry to delay detection. They will also locate, inspect, and document all fire-detection devices, alarms, and fire-suppression systems. Investigators will also search for other evidence of tampering with safety features or interference with their timely activation.
While overseeing the clearing of fire debris, the fire investigator will be on the lookout for incendiary devices in the debris, and signs of trailers used to ignite or spread the fire. It’s vital to the investigation that you approve requests from the fire investigator to collect evidence and submit it to a certified lab. Fire debris samples can reveal traces of ignitable liquid residues while components, products and appliances should be reviewed by a licensed engineer to eliminate them as possible causes of loss.
The fire investigator collects data and analyzes conditions throughout the scene, including the fire patterns and fire effects, measuring the depth of char, completing arc mapping, determining the sequence of events, fire dynamics, considering the construction type and occupancy type. The fire scene is considered together with the fire investigator’s observations of fire debris and the information collected during interviews to develop their hypothesis. Often at this stage, the fire investigator will call you to give you a report of the preliminary findings and present a hypothesis. If the evidence so far indicates the possibility of arson, it’s important to contact SIU and subrogation to inform them of this suspicion.
Investigation tools
An established fire investigator should have a variety of tools available, and depending on the complexity of the fire scene, may require your approval for additional resources. For example, a vehicle fire may call for an ASE-certified mechanical or electrical engineer to perform a failure analysis to identify and eliminate possible causes of the fire. If possible, the investigator should provide an interactive 3-D scan of all buildings and/or vehicles included in the study. Three-dimensional scans are a tool that’s becoming increasingly common which allows you to explore the loss site virtually without ever leaving your desk.
Other tools are available specifically when the hypothesis involves an intentional ignition source. Some investigators may use a handheld hydrocarbon detector, though this is rare. Another resource that isn’t commonly used is accelerant detection canines. If these dogs are brought into your investigation, it’s important to remember that they are just another tool; a scientific conclusion as to the cause of the fire cannot be drawn solely from the canine’s findings. It must be confirmed by laboratory testing.
Next, if the investigator arrives at a hypothesis of a fire “intentionally ignited in an area under circumstances where and when there should not be a fire,” the hypothesis will be tested by determining whether there is a competent ignition source that indicates arson. This can include the presence of ignitable liquids in areas where they are not commonly found, excessive fuel loads or arrangements to aid in the spread of fire from one area to another, or multiple, non-communicating points of origin. Personal items missing from the fire scene, or evidence that another crime took place, are often key indicators.
Once the fire investigator has determined a competent ignition source, resolved any contradictions presented by the data, and considered alternative origins and causes that would also fit the data collected, they will compile their findings in a report. This report should be unbiased and present a summary of the methods of the investigation as well as all of the data supporting the conclusion. It also should include photographs and appendices of relevant material.
The origin of some fires is not able to be determined. Reasons can include insufficient information obtained, prohibiting the ability to come to a scientifically certain conclusion. However, a qualified fire investigator will follow the steps laid out by the NFPA on every investigation, regardless of the size or complexity of the scene. If arson, as defined by the NFPA 921, is determined to be the cause of the fire, an essential element in the investigation will be an expert who can support this conclusion with data. If you utilize the above-mentioned recommendations, it will help you choose your expert wisely!
Bret Kittle (bkittle@donan.com) joined Donan in 2016 and is currently a lead fire investigator based out of the Nashville, Tennessee office after 26 years of fire service. Bret is a certified fire investigator with the International Association of Arson Investigators and a certified fire and explosion investigator with the National Association of Fire Investigators, and a graduate of the Ohio Fire Academy and the National Fire Academy.
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