Fire destroys physical evidence, but it rarely erases what people saw, heard and smelled. Witness information is often the fastest way to narrow the area of origin, establish a timeline and identify potential ignition sources. NFPA 921 treats witness statements as data to be collected and tested like any other. The Utah Chapter IAAI has long emphasized these skills: the chapter's older Tools page offered a Canvass Report and a Home Owner Interview Form, and the 2009 annual seminar featured interview and interrogation training presented by Patrick Kelly, a former FBI special agent and polygraph examiner. This article summarizes practical techniques for interviews and canvassing.
Who Should You Talk To?
- The 911 caller and anyone who reported the fire.
- First-arriving firefighters and police officers, whose observations of fire location, smoke color, door and window positions and ventilation are often the most objective early data available.
- Occupants, owners and tenants, who know the building, its contents and recent activities.
- Neighbors and passersby, who may have seen the fire's early stages or people and vehicles nearby.
- Maintenance workers, contractors and utility personnel who recently worked on the property.
- Insurance representatives and other interested parties, where appropriate.
The Neighborhood Canvass
A canvass is a systematic effort to identify people who may have information. Timing matters: memories fade and people leave, so start as early as practical.
Plan the canvass
Define the area to be covered, considering sight lines, wind direction and routes to and from the scene. Assign investigators to specific streets or buildings so nothing is missed or duplicated.
Record every contact, and every non-contact
A canvass form should record each address visited, the time, who was contacted, and whether they had information. Record addresses where no one answered so they can be revisited. A consistent form, like the chapter's legacy Canvass Report, makes it easy to show later that the canvass was thorough.
Look for cameras
Doorbell cameras, home security systems, business surveillance and traffic cameras can provide precise timelines. Many systems overwrite footage quickly, so identify them early and ask owners to preserve recordings, using proper legal process when required.
Ask open questions
Useful questions include: What did you see, hear or smell? When did you first notice something? Where exactly was the smoke or fire? Did you see anyone or any vehicle nearby? Has anything unusual happened in the area recently?
Interviewing Occupants and Owners
Occupants are usually the best source of information about the building and what happened before the fire. A structured approach, such as the chapter's legacy Home Owner Interview Form, helps ensure nothing important is overlooked. Topics typically include:
- A timeline of the day, including who was present and when they left.
- Activities before the fire: cooking, smoking, candles, heating, laundry, charging devices or using tools.
- The location and condition of appliances, cords, heaters and electrical equipment.
- Any recent electrical problems, such as flickering lights, tripped breakers or warm outlets.
- Recent repairs, renovations or changes to the building or its contents.
- Security: which doors and windows were locked, who had keys, and any prior incidents.
- Smoke alarm presence and operation.
- Insurance and financial information where relevant and lawful to obtain.
Interviewing First Responders
Firefighters and officers see the fire at its earliest stages, but their observations are easily lost once the incident ends. Ask the first-arriving crews where they saw fire and smoke, which doors and windows were open or forced, how they entered and ventilated, where they applied water, and whether they moved contents or victims. Their account of suppression activity is essential for interpreting fire patterns and flow paths correctly.
Techniques That Improve Interview Quality
Build rapport
Many people you interview have just lost their home or belongings, or may have lost a family member. Introduce yourself, explain your role and show respect. People who feel respected tend to share more information.
Use open-ended questions and listen
Begin with a free narrative: "Tell me everything you remember from this morning." Follow with specific, non-leading questions. Avoid suggesting answers, and resist the urge to fill silences.
Separate witnesses
Interview witnesses separately whenever possible, so that one person's account does not shape another's.
Document accurately
Record who was present, the date, time and location, and the person's own words for key statements. Follow your agency's policy on audio or video recording. Sketches drawn by the witness showing where they saw fire or smoke can be very valuable.
Re-interview when needed
As the scene examination progresses, new questions will arise. A follow-up interview to clarify details is normal and often productive.
Interview Versus Interrogation
An interview is a non-accusatory conversation to gather information. An interrogation is an accusatory process directed at a person believed to be involved in a crime. The legal requirements differ significantly, including when rights advisements are needed and how statements may be used. Investigators should follow their agency's policies and consult prosecutors or legal counsel when an investigation may become criminal. Private-sector investigators operate under different rules and should be clear about their role.
Evaluating What You Hear
Witness statements are data, not conclusions. People make honest mistakes about time, distance and sequence, and perception is affected by stress, lighting and vantage point. Test statements against physical evidence, fire dynamics and other witnesses. When a statement conflicts with the physical evidence, investigate the conflict rather than discarding either piece of information. Our article on NFPA 921 and the scientific method explains how witness information fits into hypothesis testing, and why investigators must guard against bias.
Interviews at Specialized Scenes
At fatal fire scenes, coordinate interviews between agencies so witnesses are not questioned repeatedly without purpose. At wildland fires, early observations from first responders and nearby residents are critical to locating the general origin area. For vehicle fires, the last driver's account of warning lights and smells often points toward the system involved.
Common Mistakes
- Waiting too long to canvass and losing witnesses or video.
- Asking leading questions that shape the answer.
- Failing to document negative responses and unanswered doors.
- Treating the first explanation offered as the answer.
Build Your Interview Skills
Interviewing improves with training, practice and feedback. The IAAI's online training includes modules on witness interviewing, and the Utah Chapter's annual conference has included interview training in the past. Check the Training page for upcoming sessions, browse more investigator resources and consider joining the chapter.