Fire and Arson Scene Investigation: A Guide for Public Safety Personnel

National Institute of Justice


  • Message From the Attorney General
  • Message From the President of the University of Central Florida
  • Technical Working Group on Fire/Arson Scene Investigation
  • Preface
  • Acknowledgments
  • Introduction
    • Why Investigate Fires?
    • The Fire Problem in the United States
    • The Problem of Fire Investigations
    • Then Who Investigates Fires?
    • Why This Guide?
    • Training Criteria
    • Background
  • Fire and Arson Scene Evidence: A Guide for Public Safety Personnel
    • Section A. Establishing the Role of First Responders
      • Observe the Fire and Scene Conditions
      • Exercise Scene Safety
      • Preserve the Fire Scene
      • Establish Security and Control
      • Coordinate Activities
    • Section B. Evaluating the Scene
      • Introduce Yourself and Your Role as the Investigator
      • Define the Extent of the Scene
      • Identify and Interview Witnesses at the Scene
      • Assess Scene Security at the Time of the Fire
      • Identify Resources Required to Process the Scene
    • Section C. Documenting the Scene
      • Photograph/Videotape the Scene
      • Describe and Document the Scene
    • Section D. Processing Evidence at the Scene
      • Identify, Collect, and Preserve Evidence
      • Prevent Contamination
      • Package and Transport Evidence
      • Establish and Maintain the Chain of Custody
    • Section E. Completing the Scene Investigation
      • Release the Scene
      • Submit Reports to the Appropriate Databases
  • Appendix A. Documentation Examples
  • Appendix B. Additional Reading
  • Appendix C. National Resources
  • Appendix D. Points of Contact
  • Appendix E. List of Organizations


It is a capital mistake to theorize before one has data. Insensibly, one begins to twist facts to suit theories instead of theories to suit facts. —Sherlock Holmes, A Study in Scarlet, by Sir Arthur Conan Doyle

As Sherlock Holmes pointed out, many types of investigations are susceptible to prejudgment, but few as often as fire scene investigations. Fires, by their destructive nature, consume the evidence of their initiation and progress as they grow. Investigations are compromised, and often scenes are further destroyed by the activities of the fire service, whose primary responsibilities are to save lives and protect property against further damage. Fire scenes often involve all manner of public entities: emergency medical, law enforcement, and fire services. Public utilities such as gas and electric companies may be involved. Passers-by, owners, tenants, customers, delivery agents all may have relevant information. The press and curious individuals attracted to large fire scenes can complicate investigations, as they make security a necessity. As has frequently been said, “A fire investigation is like a picture puzzle. Everyone involved with it has some of the pieces, but no one has the whole picture. It is up to the investigator to gather enough of these pieces together to solve the puzzle.”

Why Investigate Fires?

Since Roman times, civil authorities have recognized the threat that fire represents, not only to the well-being of individuals, but also, and perhaps more importantly, to the welfare and security of the community as a whole. In the days of wooden walls and roofs and straw-covered floors, any fire could ravage an entire city. So, it was in the interest of all concerned to investigate fires and establish how they began. Civil authorities attempted to control the fire risk by assessing penalties if an accidental fire was allowed to get out of control. Dangerous practices, such as leaving cooking fires unguarded, were identified and controlled.

William the Conqueror issued an edict that cooking fires be damped or covered after a particular time of evening so that unattended fires could not flare up. This policy of couvre feu (cover the fire) gave rise to the “curfew” of today. If authorities could determine the fire was deliberately set, the perpetrator could be identified and punished. Some of the oldest English common laws regarded arson to be the crime of burning the house or dwelling of another. The crime of arson was considered to be such a danger that it was punishable by death.

The same rationale applies today. Fires of accidental cause need to be identified, so that dangerous practices, such as filling kerosene room heaters with gasoline, can be eliminated by public education, or so that defective or dangerous products, such as instant-on televisions or room heaters with no overheating or tip-over protection, can be taken off the market or modified so they no longer pose a significant fire risk. Fires of incendiary (i.e., deliberate) cause must be detected, so that the firesetter can be intercepted before doing more harm and punished as necessary.

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The Fire Problem in the United States

According to the National Fire Incident Reporting System (NFIRS) of the U.S. Fire Administration (USFA), Federal Emergency Management Agency, the United States has one of the highest per capita fire death rates among industrialized nations. In 1997, the U.S. fire death rate was 15.2 deaths per million. This was reflected in approximately 4,050 deaths and more than 23,000 injuries for that year alone. Nearly 2 million fires occurred in 1997, with a total estimated dollar loss of $8.5 billion.

Thirty-one percent of these fires were in structures. Residential fires comprised 23 percent of all fires and 74 percent of all structure fires. Eighty-four percent of all fatalities occurred in homes. In addition to structure fires, each year hundreds of thousands of vehicle and outside fires occur. In 1997, vehicle fires accounted for nearly 400,000 incidents, resulting in approximately 450 civilian deaths and 1,700 civilian injuries. Outside fires were estimated at more than 700,000 occurrences, accounting for 40 percent of the total number of reported fires.

Arson fires (defined as incendiary/suspicious in NFIRS) comprised almost 16 percent of all reported fires in 1997 and accounted for more than $554 million, or 15 percent, of the total estimated dollar loss. Since all fires are considered accidental until they can be proven to be intentionally set, the reported numbers are probably very conservative. There is also reluctance to report arson fires, as it is feared that it may cause a negative impact on the community or its economy.

While the general trend in numbers of fires and fire deaths has shown a steady gradual decline over the past decade, the overall costs are still significant. A continuing effort must be made to accurately identify the exact origin (where the fire started) and cause (the factors that brought the ignition source and first material ignited together) of all fires. This will assist in learning more about how to prevent fires in the future. Perhaps more important are preventive measures such as installing working smoke detectors and residential sprinklers in every home and using public education programs to effect behavior change.

The Problem of Fire Investigations

The advantages of accurate and thorough fire investigations are obvious. The United States is one of the few countries where public authorities have statutory responsibility to investigate all fires and determine their origins and causes. While this may appear to be a solution to the problem of fires and arsons, a number of major complications in fire investigations exist in the United States:

  • A fire can be a complex event whose origin and cause are not obvious. Investigators may have to expend considerable time and effort before the cause can be identified. This is the area where Holmes’ dictum is especially applicable. Without gathering data, the investigator can only guess at what might have caused the fire, based on circumstances alone. The training and preparation of qualified investigators are often costly and time-consuming, requiring dedication to the profession over many years.

  • The destructive power of the fire itself compromises evidence from the outset. The larger a fire becomes and the longer it burns, the less evidence of causation will remain. In some fires, sufficient data to establish the origin and cause (i.e., evidence) do not survive, no matter how diligent the search or well prepared the searcher. This destruction may be exacerbated by the normal and necessary duties of fire personnel carrying out rescue, suppression, overhaul, and salvage tasks.

  • The complexity of the threat a major fire presents to the health and welfare of the community means that representatives from law enforcement, fire, rescue, and emergency medical services; hazardous materials teams; utility company personnel; health and safety officers; and other public agency personnel may be on hand and may conduct some obligatory official duties. The presence of so many people, in addition to members of the press and the public who were attracted by the sights and sounds of a major fire, offers yet more chances for scene security to be compromised and critical evidence to be contaminated, moved, or destroyed.

  • Responsibility for the investigation of fires is split. While the fire service has the primary civil responsibility to establish a fire’s cause, if the cause is determined to be accidental, the scene is released to the owner or the owner’s insurance company for further examination. If the conclusion is that the fire was purposely set, a crime has been committed and law enforcement authority is needed to investigate the crime. This often means releasing the scene and evidence to a local law enforcement agency. Where local law enforcement has inadequate resources or personnel, an outside agency such as a State fire marshal, or even a Federal agency (e.g., the Bureau of Alcohol, Tobacco and Firearms [ATF]) may be asked to investigate. Any such transfer may cause complications in establishing lines of authority. In some agencies, investigative teams are composed of individuals from both law enforcement agencies and fire departments so that the continuity of the investigation can be maintained through both civil and criminal phases. In a few cases, individuals have both law enforcement and fire authority, thanks to extensive cross-training, so cases are handled from start to finish by a minimal number of trained, motivated investigators.

  • A lack of commitment to conduct fire investigations exists on the part of some law enforcement and fire agencies. Because of the demand for rescue, hazardous materials, and emergency medical assistance, in addition to their traditional duties of fire suppression, fire departments often find themselves with fewer resources to stretch to cover all obligations. As a result, the less visible responsibilities of fire investigation and fire prevention are often scaled back. These cutbacks occur despite the advantages that aggressive programs in both areas could provide to the individual department and to the community it serves: Preventing a fire means there is no loss of life or property, no risk to personnel, and no equipment costs; investigating a fire means that potential accidental or criminal threats to the community may be averted in the future. Law enforcement agencies, facing similar overwhelming demands for their time, might prefer not to become involved in cases where the scene is destroyed or at the very least compromised, time-consuming scene examination and interviews are required, and the resulting evidence is often complex and circumstantial (meaning prosecutors may not want to use it even if it is properly and completely collected).

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