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A Field Guide to Incident Analysis


Ed Comeau
Ronald F. Tunkel

When You’re the First Officer at a Suspicious Scene, 
You’ll Be Glad You Read...

You’re on the scene of a fire, and you’ve just finished getting it under control. Your crew is completing overhaul, but something has been nagging at you. What is it about this fire? The operation went one was hurt...there were no victims that had to be rescued. Then you remember...

This could be any fire...any time or anywhere. While a number of fires are caused accidentally, every fire should be considered “guilty” until proven innocent, until you fully understand its origin. There are times when it may appear obvious what started the fire. Of course—it was a cigarette. Or electrical malfunction. Or a stove. Or children playing with matches. On the other hand, was it? Are you really sure?

According to the National Fire Protection Association’s 2000 arson report, “Only about 2 percent of set fires lead to convictions.” While there are a number of factors that contribute to this low figure, one of the first steps in building a successful prosecution is identifying that a fire may indeed have been deliberately set. If the cause of a fire is not accurately determined at the very beginning, then there may be no perceived need to follow up and attempt to determine who had the means, motive and opportunity to set it.

The NFPA reports that arson fires are at a 22-year low. However, despite this fact, incendiary and suspicious fires are the largest cause of property damage in the United States.

It’s important that the company officer have an understanding of some of the basics behind arson and arsonists. Just as in emergency medicine, if the responder has an understanding of a disease, the symptoms will help in diagnosing the problem.

A Question of Motives

There are generally six recognized motives for arsonists:

Vandalism. One of the frequent targets of vandalism-motivated arsonists is schools.

Excitement. Arsonists who fall into this category are the thrill-seekers, or people who are looking for attention.

Revenge, which can include personal, societal, institutional or group retaliation.

Crime Concealment. Arson is a useful tool, and can aid and abet a primary crime being committed. That crime can range from theft to homicide, with the fire being used to hide the crime.

Profit. Arsonists can either profit directly from setting the fire, by collecting on an insurance policy, for example, or indirectly by eliminating a money-losing business.

Extremist. Arson can be a weapon for political purposes. Targets include politically controversial sites, such as abortion clinics and mink farms.

Interview Strategies

Besides physical indicators, there is a wealth of information that can be obtained from witnesses who are at the scene during firefighting operations. These are very crucial witnesses, because they may have valuable information, but are probably going to leave the premises as soon as the fire is over and there isn’t anything left to watch.

The first-due officer can approach these people and try to learn if anyone has information that could be of value and whether further investigation is needed. If no effort is made to talk to these people, the critical information they might have is going to walk away when they do.

Studies indicate that 90 percent of all the information we process is received subconsciously. Bearing in mind that both witnesses and suspects may be present at the fire scene, the following are some suggestions for the officer who needs to quickly identify which persons should be interviewed and what may be learned from them:

• Initial observations are crucial. It can prove invaluable if first responders are able to capture images of the people present in the crowd. Many arsonists have been identified simply by being observed on-scene at different fires. Having a photographic record of who is present can allow you to identify and interview individuals later, if necessary.

• In sizing up the crowd, trust your instincts. Studies of arsonists suggest that you should first pay attention to someone who is alone in the crowd. If you do start to focus on someone, you should consider the following two questions when observing and analyzing their behavior:

Is the behavior EXPECTED or EXCESSIVE?


An example of this point occurred in a recent case where the parents of five children who were killed in a fire were standing around outside the burning home, and calmly asking bystanders for cigarettes while their children were still trapped inside. This behavior was inconsistent with the actions of most living creatures whose young are in the process of horribly dying.

• It’s important to ask the right questions. Many upstanding people will not volunteer information to law enforcement simply because they’re afraid or because of their personal policy of “not getting involved,” “minding their own business,” or “not being a snitch.” At the beginning of an investigation, however, you may miss critical witnesses and information if you do not ask the right questions, so it’s crucial that you make the effort as much as possible.

• Be direct in asking questions. We’re not dealing with Miranda situations or complex interview strategies at this point. Ask “Did anyone see anything?” “Do you know who did this?” “What happened here?” “If anyone has information, would they please help us?” This last question, the request for help, is a powerful motivator for reluctant witnesses. People are programmed to want to help one another and to do right. It applies to the most saint-like of citizens and to the most sinister.

• It’s important that you both listen and observe. Too often we all make the mistake of asking a question and rather than devoting our full attention to the answer, we are already thinking of what we will say or ask next. A great deal of information is often revealed by how people answer our questions.

• A direct question should receive a direct answer; and anything else should be considered suspicious. In answer to the question “Do you know who started the fire?” a truthful person would either say “yes” or “no.” Conversely, if the response is a question, such as “Why do you think I would know who did it?” or “Do you suspect me?” or “Why should I help you?” then the officer should realize these are not direct answers and suggests that the speaker may be concealing information.

• Other classic indicators of deception are stalling mechanisms that the speaker uses to “buy” time and consider what he should say. Examples include asking you to repeat the question, or repeating the question himself. Stuttering, coughing or clearing the throat may be used to buy precious seconds while the speaker thinks of what to say.

• There are times when indirect questioning is a valuable tactic, too. In response to indirect questions, listen closely to what the subject says and again ask yourself if what he is saying is consistent with what a person who is truthful or not involved would say.

For example, when most people are asked what the consequences should be for a person who has committed a crime of violence, the answer usually is prosecution, prison, and/or execution. A guilty person may say something such as “community service” or that the offender needs help. Any answer that minimizes the exposure to what would be considered normal punishment should be considered suspect.

Another example can be seen in the response to the question “Is there any reason someone would say they saw you at the scene prior to the fire?” An innocent person will usually answer that with “no,” or “Well yeah, I work here and was on duty at that time.” Suspicious responses could be “Let me talk to that person”; “Who said that?” or “Well I did just happen to be in the area last night buying groceries at 2 a.m.” (in a store 20 miles from the one he usually uses!).

• Try to observe and “read” the subject’s body language. A good rule of thumb is to look for two or more odd body movements or other deceptive behaviors within the three to five seconds that follow after a question. Examples include excessive eye contact or breaks in eye contact, such as rapidly blinking eyes. The person might cover his eyes, or look away in response to specific questions.

• A deceptive person is often frightened that he may reveal the truth by what he says. Unconsciously, he may attempt to prevent this biting his lips, coughing or swallowing, or even actually covering his mouth.

• There are actions that a person will take without even being aware of them. These can be invaluable clues. If a person says “no” while nodding his head, you may consider that a “yes.” If a person is saying he is happy to speak with you, yet you notice he’s holding his chin up with a middle finger, you may well assume that he is not completely happy with you.

The crux of all of these suggestions is that no single behavior proves deception, but a number of these indicators, when displayed at a relevant point in a conversation, can be significant.

The first-due officer can play a critical role in a fire in more ways than just suppressing the fire and rescuing victims. By being able to “size up” the need for an investigation, the officer can be instrumental in helping to identify a potential arson fire and contribute significantly to the conviction of this person. Even if your department has assigned fire investigators who will arrive and determine the cause, those few initial moments may provide significant clues that you can observe and record for the investigators when they do arrive. We need to improve upon that 2 percent conviction rate, and you can be a key component in making that change. NF&R

Ed Comeau is the principal writer for, a technical writing firm. He is the former chief fire investigator for the National Fire Protection Association, was a fire protection engineer for the Phoenix Fire Department, and a firefighter for the Amherst, Mass., Fire Department. He has been involved in the development of interFIRE VR from its inception. He can be reached at .

Ronald F. Tunkel has been a special agent with the Bureau of Alcohol, Tobacco and Firearms for 13 years. His current assignment is as a criminal profiler with the National Center for the Analysis of Violent Crime at the FBI Academy in Quantico, Va.

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23 Incident Indicators

So what are the indicators that every officer should consider when sizing up a fire scene from an origin-and-cause perspective? What are the indicators that will help determine if further investigation is warranted? There are a number of them, but taken individually, they are not definitive indicators. However, several of them—taken together—might raise a “red flag” for the officer. We’ve organized 23 of these indicators into a list you can detach and refer to later.

Some of these indicators include:

1. Who called in the alarm? (What kind of information did they give to the dispatcher? Was it overly detailed, or did it include information that the average caller wouldn’t know?)

2. As you were pulling up on the scene, what color was the smoke and the fire? (Was it an unusual color, considering the fuel that was burning? Where was it coming from? Multiple locations? Were there any unusual sounds, such as explosions?)

3. Were you delayed in responding because of a false alarm or a small fire, such as a trash fire? (Or were there barriers, such as locked fences or obstacles, that slowed your attack? Had the hydrant been tampered with? These tactics could be used to allow the fire more time to grow.)

4. Was there anyone in the crowd that you have seen at fires before? (Did anyone look as if they were behaving unusually?)

5. Was there any unusual evidence, such as containers, matches, lighters, etc., that might not normally be found in the area? (According to a joint study conducted by the ATF and FBI, over 50 percent of the serial arsonists studied left items at the scene of their fires.)

6. Had doors been propped open, or holes made in floors or walls, to help accelerate the spread of the fire from one area to another?

7. Were there any vehicles leaving the scene as you pulled up, or shortly after you arrived? (Most people are going to stay to watch a fire, rather than leave.)

8. Have you been to this property before? (Does it have a history of fires? This could be an indicator of someone attempting to burn the building, either for profit or for revenge.)

9. Were there signs of forced entry such as broken doors, locks or windows? (If the fire is determined to be incendiary, the lack of any evidence of forcible entry can be as important as its existence.)

10. Were there multiple points of origin? (To ensure greater destruction, and to make suppression efforts more difficult, an arsonist could set multiple fires throughout a building.)

11. Was a burglar alarm sounding when you arrived? (If it was equipped with an alarm, did it go off when you made entry? If not, why not?)

12. Was the building’s fire alarm or sprinkler system impaired in some way? (An arsonist could do this to ensure that the fire was not detected or suppressed until it had a chance to do significant damage.)

13. Did you smell anything unusual?

14. Was the behavior of the fire unusual? (Did it take an unusual amount of time or water to get it under control, considering what should normally have been burning?)

15. Did the fire start in an unusual location where there would normally not be any source of ignition? (For example, did the fire start in a pile of debris outside the building and then extend into the building.)

16. How was the owner’s behavior when he or she arrived? (Unusually calm? Extreme mood swings? How was he dressed? For example, if the fire occurred in the middle of the night, was the owner impeccably groomed upon arrival?)

17. Did the neighbors have any information that might point to this being an unusual fire? (Arguments, past fires, etc.)

18. Did the contents seem appropriate? (For example, was anything missing that should normally be in place, such as stock or equipment? Were the clothes closets empty?)

19. Were the windows covered to delay the fire being seen from the exterior? (This would give the fire a chance to grow before being detected.)

20. Was anyone taking pictures or videotape of the fire when you arrived?

21. Are there unusual burn patterns? (Trailers that would lead the fire from one area to another may leave a distinctive pattern on the floor, as could flammable liquid.)

22. Is the property for sale, or in distress? (Is it under any orders for repairs to be made? Having a fire might be a convenient method to avoid expensive repairs.)

23. When water was applied, did the fire react in a different way than you would have expected?


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