Fires have a way of becoming court cases. The condition of physical evidence can be critical to the outcome of any criminal or civil court case. These days, attorneys and courts are becoming more involved in the business of public safety, and the efforts fire departments make to protect evidence are being scrutinized as never before.

Until a fire scene is turned over to fire investigators, the firefighter and fireground commander must take steps to secure the scene and any evidence within it. These steps will help the investigation and will help the department avoid any accusation that it compromised valuable court evidence.


Preserving the fire scene is critical to a successful arson arrest and prosecution. It also helps determine the truth in civil litigation, whether there should be insurance payment, and which insurance company is ultimately responsible for the payment. Departments are now moving away from wholesale post-fire operations in which fire scenes are unnecessarily disturbed, emptied, or overhauled. Instead, departments should perform the minimum amount of overhaul consistent with the objectives of detecting fire and preventing rekindle. This philosophy should be reflected in your standard procedures. Overhaul what is needed, but avoid unnecessary destruction.

During suppression, avoid the excessive use of water, especially at the suspected seat of the fire, as this may be the area of origin. Avoid dragging hoses back and forth through the suspected room or area of origin, as they can move, damage, or destroy evidence. If possible, leave hoses in place until an investigator can examine the area. As you check for extension, make only small holes in walls, ceilings, and floors to preserve patterns that may be visible over a larger area. If the entire wall’s covering has been removed, these larger patterns could be destroyed. Fire evidence is notoriously fragile and is easy to move around or destroy. Extinguish everything in its place. Avoid moving still-smoldering furniture, appliances, and equipment unless leaving them in place will add to the fire loss.

During and after overhaul, the best way to keep a fire scene intact is to treat it as a crime scene even if the fire appears accidental. The incident commander (IC) should make sure no unauthorized persons are allowed in without the investigator’s permission. If a specific operation is needed, only those firefighters and officers necessary to the task should be permitted in. Acting at the IC’s direction, the firefighter can use available tools to mark the scene such as barriers and barrier tape (photo 1). Make sure that you cordon off an area large enough to encompass potential evidence that might be away from the structure itself. Include burned areas, areas of ingress and egress, areas where evidence is visible, and areas where evidence may be concealed.

(1) Barrier tape is used to cordon off a building as well as the area surrounding it. (Photos by authors.)

At the entrance to the structure or cordoned-off area, the IC should post a firefighter whose job is to turn away curious members of the public, other firefighters, and even fire officers who don’t have a specific assignment. If necessary, ask the police to assist in this task. The person at the entrance should record the names of persons entering and leaving the scene, along with the time of entry or exit and whether anything was removed. Members operating within the structure should be prepared to tell the investigator where they were and what contents they disturbed during the operation.


Like the scene itself, fire evidence should remain undisturbed as much as possible following extinguishment. Department members who notice potential evidence should notify the incident commander or investigator as soon as possible. Do not handle or move an item of evidence unless necessary to prevent its immediate damage or destruction. If needed, take simple steps to guard the evidence, such as marking it with a flag (photo 2) or a marker (photos 3, 4, and 5). Better yet, cordon off the area with fire scene tape. Although some texts suggest covering small items with a box, this may not be appropriate in every case, because a box will not alert others to the presence of the item and the box itself could potentially come in contact with a fragile item underneath. Remember that potential evidence items could include incendiary devices, ordinary fire-starting materials (such as matches and lighters), ignitable fluids, burglary tools, tool marks, weapons, documents, footprints, tire impressions, and the like (photos 6 and 7).

(2) An inexpensive flag indicates the presence of evidence.


(3) An evidence marker notifies personnel on the scene to avoid disturbing an item. Make sure personnel do not take the presence of the marker as an invitation to visit the area and view the item.


(4) This evidence marker was made from an inexpensive yellow putty knife available at any home-improvement store.


(5) A traffic cone marks the location of potential evidence. When using a traffic cone, be sure to notify the IC and investigators that it is marking evidence. Replace the cone with an official evidence marker when one becomes available.


(6) A pill bottle at a fire scene could be evidence of a crime, such as a drug crime, that may or may not be related to the fire.


(7) A fragile paper match was discovered near a fire scene.

If human remains are found, do not touch or move them once it is determined that the person is deceased and cannot be resuscitated. Fatal fires always result in intense investigations. Undisturbed human bodies and the immediate area surrounding them can provide significant evidence to investigators. Do not conduct firefighting operations close to a deceased person’s body, and make every attempt to reduce any further damage from water or fire. Suspend overhaul and salvage in the vicinity if at all possible. As a very last resort to prevent contamination or damage, cover the body and its surroundings with a brand new tarp or salvage cover.

Other items may not be evidence of a crime but still may be critical in determining how a fire started. Therefore, be careful not to disturb any items on the scene unless necessary-including appliances; electrical equipment; liquids; windows; and even the patterns on the walls, ceilings, and furniture (photos 8 and 9). Do not pull or knock down wallboard or plaster unnecessarily. Carefully avoid turning or moving knobs or switches or taking appliances apart (photos 10 and 11). When safe to do so, you can shut off electricity by switching only the main breaker to the building (photo 12). This will permit the investigator to examine the individual circuit breakers and gain clues about the start of the fire. Carefully avoid areas where investigators have placed markers or barrier material (photo 13). Do not open doors or drawers or pick up or move items unless necessary. Fuel your portable equipment far away from the affected structure or vehicle.

(8) This gas appliance must remain undisturbed so an engineer can inspect it. Moving it could compromise evidence, including the gas and electric connections to the unit.


(9) This outlet with partial power cord could provide electrical evidence to the investigator; personnel on the scene should leave it untouched.


(10) Leave knobs undisturbed if at all possible and if consistent with safety needs. This knob may be important to the fire investigation even if it does not appear to be at the point of origin.


(11) A gas appliance knob showing that the appliance was turned “on.”


(12) This circuit breaker panel has a well-marked main disconnect switch, which will likely remove power to all circuits served by the panel, eliminating the need to switch individual breakers.


(13) This round “chip” has the name of an accelerant-detecting canine handler and marks an area where accelerant may be present. Avoid stepping on or near this area.



Once the fire is extinguished, the fire department must maintain a continuous presence at the scene to be allowed to continue investigating. Continuous presence means department members must remain on scene and protect it until investigators arrive. If investigators can’t effectively work in a dark scene, it may need to be held overnight. Simply boarding up or fencing a scene is not enough; personnel from the fire or police department must be present. ICs should not release a fire scene without the approval of the investigators having jurisdiction.

If the fire department leaves a scene completely, it might not be allowed to return legally. There are exceptions, such as if the department has a valid search warrant or consent from the proper person in control of the property. Consult with your investigator or prosecuting attorney before making any decisions to reenter property after your department has left the scene.

When physical evidence is seized in a criminal case, the investigator or police officer must maintain the “chain of custody” of such evidence to prove that it has not been altered or tampered with after it was discovered. This means protecting it and documenting where it is kept and stored and each person who has custody of it. If you are asked to maintain custody of an item of evidence, keep it in a secure, safe place, and ensure there is documentation of (1) when it entered and left your custody, and (2) the person to whom it was given. As mentioned, this is critical in criminal cases; it is also important if the case is ever heard in civil court.


Spoliation of evidence occurs when persons or entities unnecessarily alter, lose, or destroy evidence they had the duty to protect. A finding of spoliation can result in sanctions against a party in court or even legal liability in extreme cases. For example, spoliation could happen when a person unnecessarily takes an appliance apart without notifying the manufacturer or seller; tampers with connections such as plugs and switches, which are likely related to the cause of the fire; or knowingly disposes of evidence without contacting interested parties such as manufacturers, owners, or insurance companies.

Fire companies can help protect the department from spoliation claims by taking steps to preserve fire scenes and evidence. Also, consult with legal counsel about policies or guidelines that address the handling of evidence. If a case is not criminal, it might be preferable to avoid the responsibility that comes with seizing evidence; instead, the department may choose to secure the scene and caution the owner or occupant to protect critical areas and not to enter them. You can mark a fire building or room with tape (photo 14) or a particular item of interest with tape or a special tag (photos 15 and 16). Investigators and commanders can encourage persons to identify and notify interested parties about fire scenes and potential evidence left within the scenes. Interested parties can include landlords, renters, product manufacturers and sellers, builders, repair people, installers, and the insurance companies that insure these various parties.

(14) Fire scene tape is used to prevent access to a room within a structure.


(15) An appliance of interest has been marked with warning tape to remind the occupant not to touch it.


(16) An evidence warning tag notifies personnel and the property owner not to disturb an item.

Incident command at the scene of a fire involves many decisions. A commander who takes into account the need to preserve the scene and the evidence will assist the department and other parties involved in the investigation. This will help resolve any criminal prosecutions or civil cases and improve the department’s public service product.

GEORGE A. CODDING is a state fraud prosecutor in Denver, Colorado. In the past, he worked as a deputy district attorney and an insurance litigator. He also works as a fire investigator for the Louisville (CO) Fire Protection District and chairs a multiagency fire investigation team. He has 18 years of experience as a firefighter and fire officer. He has been certified in Colorado as a peace officer, firefighter II, and EMT and is a certified fire and explosion investigator through the National Association of Fire Investigators. He is a member of the International Association of Arson Investigators, including its Training and Education and Attorneys Advisory Committees.

JOHN A. BOHN is a fire investigator for the Mountain View (CO) Fire Protection District and the Longmont (CO) Fire Department and a reserve deputy/investigator for the Weld County Sheriff’s Office. He has 16 years of experience in investigations and was recognized as Arson Investigator of the Year in 1997 by the Colorado Advisory Committee on Arson Prevention. He is certified as a peace officer and firefighter II in Colorado. He has received CFEI certification from the National Association of Fire Investigators and CFI certification from the International Association of Arson Investigators. He has testified as an expert witness in fire investigation.

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