Chapter 12 – Complex Investigations

Part 1 – Chapter Objectives, Introduction, Site and Scene Safety, and Interested Parties

Knowledge Objectives

After studying this chapter, you should be able to:

Identify the interested parties in a complex investigation.
(NFPA 1033: 4.1.4, p. 293)
Describe the basic information and documents needed to manage a complex investigation.
(NFPA 1033: 4.1.4; 4.1.6, pp. 293–294)
Describe the coordination necessary when conducting a multiparty investigation.
(NFPA 1033: 4.1.4, pp. 293–299)
Describe the logistics involved in complex investigations.
(NFPA 1033: 4.1.4, pp. 293–299)
Describe the organization and management of a major loss investigation.
(NFPA 1033: 4.1.4; 4.2.1, pp. 293–299)
Describe the importance of communication among interested parties.
(NFPA 1033: 4.1.4, p. 294–295)
Explain the considerations required for governmental inquiry into fire investigations.
(NFPA 1033: 4.1.4, p. 298)
Discuss site and scene safety considerations for complex investigations.
(NFPA 1033: 4.2.1, pp. 295–297)
Describe the special investigative considerations at a fatal fire scene.
(NFPA 1033: 4.4.1, pp. 299–305)
Describe the death-related pathological and toxicological examination of fire and explosion victims.
(NFPA 1033: 4.4.1, pp. 301–304)
Identify and describe postmortem tests and documentation.
(NFPA 1033: 4.4.1, pp. 308–309)
Identify and describe the important aspects of a death investigation.
(NFPA 1033: 4.4.1, pp. 307–310)
Describe the special investigative considerations for a fire that caused injury.
(NFPA 1033: 4.4.1, pp. 307–310)

Skill Objectives

After studying this chapter, you should be able to:

Assist in drafting protocols between parties when given incident and investigative information.
(NFPA 1033: 4.1.4, pp. 293–294)
Develop an investigative flow chart for conducting a large loss investigation when given incident information.
(NFPA 1033: 4.1.4, p. 295)
Evaluate a body for details about the fire scene.
(NFPA 1033: 4.4.1, pp. 300–305)
Secure a body as evidence.
(NFPA 1033: 4.4.1, p. 305)
Evaluate an injured victim for details about the fire scene.
(NFPA 1033: 4.4.1, pp. 305–307)

Introduction

An investigation may be complex because of its size, scope, and/or duration. A fire investigator may become involved in a complex investigation when a fire:

Occurs in a very large occupancy building.
Involves a loss of life or high-value property loss.
Requires coordination with various other investigators or team members.

A public-sector investigator may be required to lead a team of investigators and other professionals in an occupancy with several floors or areas. The investigator may also have to coordinate the investigation with different types of professionals, such as machinery operators, coroner investigators, or building officials.

A private investigator may need to coordinate with several interested parties while multiple investigations occur simultaneously.

Managing and coordinating complex investigations may involve:

Large investigative teams of different professionals.
Investigations covering large areas or multistory buildings.
Multiple interested parties and investigators.
Fatal fires involving several investigators and professionals and their own additional complexities.

Site and Scene Safety

Site and scene safety is paramount and must be addressed early in the investigation and planning process. The site should be evaluated for safety considerations, and safety information should be disseminated to everyone who is present or may later arrive.

All parties should be reminded that structural and site safety are compromised at a fire scene. Fire scenes may be unfamiliar to people who are not fire investigators or firefighters, including:

Vehicle-equipment operators.
Engineers.
Coroner personnel.
Other participating personnel.

Every party is responsible for maintaining safety and being trained to work with the hazards present. It may be necessary to appoint a site safety person who has authority to stop activities when safety concerns arise and until those concerns can be adequately addressed.

Hazardous materials create additional, unique concerns for safety and hazard mitigation. A high level of site hazards, such as hazardous materials, may require specialized resources to ensure safety during the site investigation.

Safety concerns may be serious enough that the following measures should be considered:

A company specializing in evaluating site hazards.
Formal safety plans.
Safety officers.

Site personnel must follow the safety officer’s directions, although personnel may object to those directions and request reentry. Before anyone enters the investigation site, that person may be required to receive a preliminary safety briefing specific to the site and scene.

A record should be maintained of everyone who attends a safety briefing. Unresolved objections, including disagreements, should also be recorded and handled.

Continued site monitoring may be required for concerns such as:

Structural conditions.
Airborne contaminants.

During complex investigations, periods may occur when no investigative activities are performed because safety or environmental concerns must be mitigated before the scene examination can continue. Safety issues should be addressed in the protocol developed by the parties involved in the investigation.

Interested Party

According to NFPA 921, an interested party is:

“any person, entity, or organization, including their representatives, with statutory obligations or whose legal rights or interests may be affected by the investigation of a specific incident.”

Managing Investigations with Interested Parties

When interested parties are notified of a fire event, they often notify their insurance companies. Both the parties and their insurers may engage and send their own investigators. As a result, numerous investigators and attorneys may wish to participate in the investigation. Their roles are typically coordinated by the investigator representing the property owner or insurer.

Although coordination activities often occur during large-area and multiple-day investigations, coordination may also be needed for smaller fires. For example, when a large appliance is involved in a fire cause in a rented house, the interested parties may include:

The landlord.
The tenant.
The product manufacturer.
The parts manufacturer.
The installer.
Each party’s insurance carrier.

Interested parties will include the owner and the owner’s insurance company, as well as people or organizations that may become parties to a potential civil case. Depending on the circumstances, they may also include:

Building-component manufacturers.
Appliance-system providers.
Subcontractors and installers.
Fire-protection- and detection-system installers.
Equipment manufacturers.
Construction-material and finish manufacturers.
Service companies that serviced equipment in the area of origin.
Representatives connected to gas and electric utilities.
Representatives connected to suppression or detection equipment.
Public agencies, such as code enforcers or inspectors.

Interested parties are likely to retain their own experts, insurance companies, and lawyers. Any or all of these representatives may participate in some aspect of the investigation.

The manager of a complex investigation is responsible, in most jurisdictions, for identifying which interested parties should have access to the site. The determination depends heavily on the facts and context of the investigation. To avoid spoliation-of-evidence issues, the investigation should use an inclusive approach and ensure that no potential party is overlooked.

For example:

If a fire occurred in a newly constructed or remodeled building, interested parties would include the contractor and any subcontractors who worked in the area of origin.
If several heat-producing appliances were present in the area of origin, interested parties may include the manufacturers and installers of each appliance.

Interested parties should be identified as early as possible in the investigation process.

Notification is best coordinated with a legal advisor who can:

Help determine whom to notify.
Help locate and identify parties.
Prepare and send notices.

Even when notification is coordinated in this manner, other parties may be identified during the investigation. When this occurs, those parties should be notified. Further investigative activity may have to be delayed until they can participate.

An interested party that learns of the incident through its own sources and wishes to participate in the investigation may also approach the investigator in charge.

Not every fire requires coordination among interested parties. For example, when a large appliance is involved in a fire cause in a rented house, the interested parties may include:

The landlord.
The tenant.
The product manufacturer.
The parts manufacturer.
The installer.
Each party’s insurance carrier.

Interested parties normally include the owner and the owner’s insurance company, as well as people or organizations that may become parties to a potential civil case. Depending on the circumstances, they may also include:

Building-component manufacturers.
Appliance-system providers.
Subcontractors and installers.
Fire-protection- and detection-system installers.
Equipment manufacturers.
Construction-material and finish manufacturers.
Service companies that serviced equipment in the area of origin.
Representatives connected to gas and electric utilities.
Representatives connected to suppression or detection equipment.
Public agencies, such as code enforcers or inspectors.

Interested parties are likely to retain their own experts, insurance companies, and lawyers. Any or all of these representatives may participate in some aspect of the investigation.

For example:

If a fire occurred in a newly constructed or remodeled building, interested parties could include the contractor and any subcontractors who worked in the area of origin.
If several heat-producing appliances were present in the area of origin, interested parties could include the manufacturers and installers of each appliance.

Interested parties should be identified as early as possible in the investigation process.

Notification is best coordinated with a legal advisor who can:

Help determine whom to notify.
Help locate and identify parties.
Prepare and send notices.

An interested party that learns of the incident through its own sources and wishes to participate in the investigation may also approach the investigator in charge.

Part 2 – Basic Planning, Protocol, Meetings, and Communication Among Interested Parties

Basic Planning and Protocol

A plan should be developed for a multiparty fire-scene investigation. This plan, referred to as a protocol, lists the procedures that will be followed during the investigation.

The protocol may be:

Agreed upon by the parties.
Drafted by a party in charge, such as the property owner.
Drafted with the assistance of legal counsel.

The protocol should be provided to all interested parties before they enter the scene.

In addition to establishing investigative procedures, the protocol may assign responsibility for specific tasks, including:

Keeping the evidence that is collected.
Handling disagreements that arise.
Addressing concerns and procedures related to scene safety.

Other subjects that may be addressed include:

Costs.
Scheduling.
Communication.
Logistics.
Handling of evidence.
Documentation.
Interviews.

The protocol may include a work plan. According to NFPA 921, the work plan outlines “the tasks to be completed [during] the investigation, including the order [of tasks and the] timeline for completion.” The work plan should be developed with input from the interested parties whenever possible.

More than one protocol may be developed for a fire investigation. For example, separate protocols may be created for:

The scene examination.
Subsequent investigations or activities occurring outside the scene.
Interviews.
Evidence storage.
Laboratory examinations.
Destructive testing.

Some interested parties may object to the protocol. The method for handling potential objections and disputes should be addressed in the protocol itself. For example, the protocol could state that a new suggestion will be evaluated and implemented if the parties agree, but that the property owner has the right to make the final decision.

With the parties’ agreement or after notifying them, the protocol may be amended to reflect new information or a new procedure.

A protocol may not represent a true consensus. The scene manager, owner, or public authorities may have to override decisions on certain issues. This may occur when there is:

A safety concern.
A concern about criminal issues.
A need to protect the owner’s proprietary interests.

Meetings

A preliminary meeting should be held before the on-scene investigation begins. Its purposes are to discuss safety considerations and establish the ground rules for conducting investigative activities.

Preliminary information and discussions may also be exchanged through telephone calls or email.

Concerns that may need to be addressed during preliminary meetings include:

Safety.
Protocols.
Planning and timing.
Access.
Organizing the investigative team.
Regular meetings.
Resources.
Preliminary information.
Lighting.
Securing the scene.
Sanitary and comfort needs.
Communications.
Interviews.
Plans and drawings.
Search patterns.
Evidence identification and handling.

Additional meetings may be held as the investigation progresses. These meetings help ensure that everyone:

Is signed in.
Is reminded of safety considerations.
Is informed of scheduling changes or other changes affecting the investigation.

Only one person from each interested party should act as the spokesperson for that group. The spokesperson should have authority to make decisions on behalf of the party represented.

The investigator managing the site must coordinate access so that only authorized people enter. Access may depend on whether required safety training has been completed and whether environmental concerns remain at the site.

Communication Among Interested Parties

Communication among parties is important in major-loss investigations. Proper communication should keep parties informed about:

Safety issues.
The progress of the parties.
The schedule for scene work and examination.

A lack of communication may leave parties with the impression that evidence is being hidden or that they are not receiving enough information to protect their interests. This may lead to distrust and conflict.

Good communication and information sharing can create cooperation among the parties and support a successful site investigation.

Information Dissemination and Sharing

The process for disseminating information among the parties should be addressed early. A lack of information may cause difficulties among parties or even result in legal action.

Without adequate communication, an investigation may be affected by:

Distrust.
Disagreements concerning investigative activities.
Disputes about the timing of activities.
Management problems.

Routine communication may occur through:

Regular meetings.
Websites.
Email.
Bulletin boards.

Information sharing can expedite the investigation and provide the parties with data needed to develop an accurate analysis and hypothesis. However, information sharing may be limited by confidentiality concerns.

In some cases, confidentiality agreements may have to be signed before interviews are conducted or information is exchanged. For example, an owner may possess important information that is proprietary or that the owner does not want shared with competitors. Confidentiality concerns may sometimes be resolved when a party that receives the information signs a nondisclosure agreement stating that the information will not be shared with anyone else.

Information sharing should be encouraged so that a complete data set is available for analysis.

When legally permissible, the parties should generally share information concerning the data needed to conduct a complete analysis for hypothesis development. This may include interviews with:

The first witnesses.
People who last used or maintained a suspected piece of equipment.

Website

When an investigation involves many parties and the scene work may continue for an extended period, a secure website may help keep the parties informed.

Passwords may be used to restrict access to the entire website or selected portions. The website keeps interested parties informed about the investigation’s progress when they are not required to be, or do not wish to be, present at the scene.

A secure investigation website may include:

A schedule of activities.
A contact list.
Protocols.
Agreements.
Safety instructions.
Information or data that must be disseminated.

Scheduling

Allowing every party access during every phase of an investigation may not be feasible. Too many people in the available area can create safety problems or leave insufficient space for participants to view the activities properly.

A consensus or compromise may be needed. Possible arrangements include:

Allowing only one person from each interested party to view an activity.
Establishing audio and video feeds so the investigation can be viewed from a safe location.

Having one representative from each party present may be especially important during evidence removal and documentation when space and safety concerns prevent broader access.

Scheduling a large number of interested parties may be difficult because not every party will be available at the same time. The scene investigation will likely have to move forward despite these scheduling difficulties.

When holding the site for an extended period is not an option, the parties may need to reach a compromise. Possible measures include:

Having a substitute person attend for a party.
Thoroughly documenting the investigative activity.

Activities conducted after the scene examination, such as examining artifacts secured from the scene, are usually less time-sensitive. The parties may agree on a mutually acceptable time before those activities occur.

Good communication about scheduling allows parties to arrange their calendars as early as possible. Scheduling communication should include:

A flowchart of activities that are occurring or scheduled to occur.
The best available estimates of when activities will occur.

The protocol and flowchart developed at the beginning of the investigation are important scheduling tools and should address anticipated scheduling issues. Although accommodating every party may remain difficult, all parties should attempt to accommodate the schedule so that the investigation can move forward.

Cost Sharing

Interested parties may agree to share the costs of certain investigative activities. Cost sharing is especially likely when each party is interested in the results of an activity or requires copies of those results.

Shared costs may include:

Professional photography or videography conducted during investigative activities.
Activities related to developing drawings.
Site-safety personnel.
Personal protective equipment (PPE).
Evidence storage.
Debris removal.
Personal-comfort items.
Specialized testing of the scene environment or evidence.

Some parties may not agree to cost sharing, particularly if they believe they have little involvement in or responsibility for the fire.

Any cost-sharing agreement should be:

Obtained in writing.
Signed by the participating parties.
Established as early as possible in the investigative process.

Shared costs may include:

Professional photography or videography conducted during investigative activities.
Activities related to developing drawings.
Site-safety personnel.
Personal protective equipment (PPE).
Evidence storage.
Debris removal.
Personal-comfort items.
Specialized testing of the scene environment or evidence.

Some parties may not agree to cost sharing, particularly if they believe they have little involvement in or responsibility for the fire.

Any cost-sharing agreement should be:

Obtained in writing.
Signed by the participating parties.
Established as early as possible in the investigative process.

Part 3 – Site Management, Evidence Control, and Site Logistics

Issues in Site Management

Proper management of a major investigation provides the tools needed to:

Limit safety-related problems.
Organize investigative activities.
Handle evidence.
Address other issues that arise during the investigation.

Implementing a management system before the investigation begins benefits the process as a whole.

A site manager may be designated to manage the site and its personnel. The person managing the site may be different from the person managing the investigation itself.

Complex investigations may involve many parties conducting joint, yet independent, investigations simultaneously. People familiar with the National Incident Management System (NIMS) may be able to use the NIMS command model to manage an investigation.

Control of the Site and Scene

Control of the site may change during the investigation.

Public-sector agencies may initially control the site. After public-sector investigators complete their examination, they will often release the scene to:

The owner.
Another responsible person.
The insurance company.

Following the public-sector examination, the site owner or occupant will often have authority to determine who controls the scene.

Securing the Site and Scene

Security and controlled access are necessary at a complex fire scene to prevent:

Contamination.
Safety concerns.
Legal disputes.

The entity in control is usually responsible for security and access control. This may require:

Installing fences.
Assigning security personnel to assist with security and access.

Security personnel may be needed to monitor access to the investigation site.

The owner should be consulted when security arrangements are developed because proprietary information and valuable equipment may remain at the site.

Access should be limited and monitored. Mandatory sign-in and sign-out sheets should be used to account for everyone who enters and exits the site. Access coordination may also involve:

Name tags.
Escorts.

At the end of each investigative day, the entity in control should confirm that everyone who entered has exited and is accounted for.

Maintaining scene integrity is critical to a successful and defensible investigation. Scene integrity includes:

Preventing public access.
Preventing debris or other contaminants from being brought onto the site.
Maintaining an accurate record of everyone permitted to enter.
Maintaining an accurate record of everyone denied entry.

Scene integrity must be preserved until the investigation is complete and the evidence has been removed. Scene security may also have to continue until the site is safe for passersby and other people.

Restrictions or Requirements

Site-specific requirements for entering the fire scene may be established.

Common requirements intended to maintain scene security and safety include prohibiting:

Smoking.
Food.
Beverages.
Containers.
Wrappers.

Food may not be consumed on the site because contaminants could be ingested.

Some form of PPE is usually required to enter the site. Depending on the hazards, PPE may include:

Hard hats.
Safety shoes.
Safety glasses.

Site-specific restrictions and requirements should be addressed in the protocol and site-safety plan.

Delegation of Control and Transfer of Control

The person or party controlling the site is generally selected according to the circumstances. Control often changes as the investigation progresses.

Immediately after fire suppression, the party responsible for control may be the public-sector investigator. If the public-sector investigator determines that no crime occurred, the investigator will often transfer the site and investigation to another party, usually the owner or the owner’s representative.

Although the owner may have the legal authority to control the site, the owner may lack the necessary resources or expertise. In that situation, the insurance company or its representative may assume control. Tenant-occupied spaces may create additional questions of control that require legal consultation.

Transfer of control should be planned in advance to ensure an orderly transition. The party relinquishing control should provide information concerning:

Changes made to the site.
Evidence that has been secured.
Safety issues.

A party may continue to participate in the investigation after relinquishing control. For example, a public official may determine that the fire was likely accidental while continuing to participate in a joint investigation with private parties.

Release of Information

Release of information to the public or media should be addressed early, particularly when a fire produces a large loss.

Public authorities and their public information officer (PIO) usually handle this responsibility.

When a large-loss incident involves multiple public jurisdictions, every public jurisdiction should provide a PIO. These officers should operate through a joint information center (JIC). Members of the JIC should manage information releases that are consistent among the participating jurisdictions.

Private parties are unlikely to release information except through an owner representative. The investigator generally should not participate in releasing information to the public.

Evidence Control

Handling evidence is another important aspect of managing a complex investigation. An evidence custodian is designated to manage all aspects of the evidence-control process.

The protocol or a separate agreement should establish how evidence will be:

Identified.
Documented.
Collected.
Preserved.
Transported.
Stored.

When public-sector authorities are conducting a criminal investigation, their requirements may determine the methods used for evidence collection and storage.

Evidence-control arrangements should also identify:

Who may access the evidence after it is stored.
How information concerning the evidence will be distributed.
How proposed examinations or testing will be handled.

All interested parties should be allowed to document and view evidence before it is changed or removed from the site. Evidence should be removed in an agreed-upon manner, usually following recognized practices identified in NFPA 921, Guide for Fire and Explosion Investigations.

Evidence removal and the chain of custody should be carefully documented.

Collected evidence should be stored in a locked facility with fire-protection features. The parties should agree on the cost of storage. This cost is usually assumed by the owner’s insurance carrier.

Keys or security access usually remain with the owner’s representative. Multiple locks may sometimes be used so that no party has exclusive access to the evidence.

Interested parties should agree on access to view the evidence. When evidence is viewed, the activity should be open to all parties.

Nondestructive examinations should be permitted to allow evidence to be viewed and documented. Other interested parties should be notified when a nondestructive examination will occur, but they do not need to be present.

When disassembly or destructive examination of evidence will occur, spoliation concerns require all interested parties to participate in the examination and permit them to have their own experts present.

A specific examination protocol may be developed. It should include:

Identification of the laboratory where the examination will occur.
The date of the examination.

Site Logistics

Numerous coordinating activities may be required to allow an investigation to proceed safely and without conflict. Logistical planning should also identify and address the individual needs of investigators and other personnel at the scene.

Many logistical needs require preplanning and may need to be included in the protocol or work plan.

Logistical planning may address:

Detailed scene-investigation activities.
Environmental issues.
Trash-collection services.
Toilets.
Equipment.
Security personnel.

Identifying and obtaining the equipment needed for an investigation is part of preplanning. Required equipment may include:

Large equipment for lifting ceilings or walls.
Equipment for removing debris or evidence.
Laborers.
Small hand tools.

Human resources needed for an investigation may be obtained by retaining a construction company. Some construction companies are equipped to provide this type of assistance.

Transportation may be an issue at some large sites. Parties may require transportation:

From a remote parking area to the site.
To and from a checkpoint.
From the scene to an evidence-storage facility.

Transportation planning should give special consideration to large evidence items.

The site may require an area for cleanup or decontamination, particularly when hazardous materials are present. When materials create a contamination hazard if taken outside the scene, decontamination personnel and equipment may be required.

Decontamination arrangements may include:

A changing area.
Washing facilities.
Showers.

Other logistical considerations include:

Communication among parties at the site.
Lighting or spotlights.
Ice and snow removal.
Heating the scene.
Break and shelter areas.
Food and water.

Many logistical needs require preplanning and should be included in the protocol or work plan.

Logistical planning may address:

Detailed scene-investigation activities.
Environmental issues.
Trash-collection services.
Toilets.
Equipment.
Security personnel.

Identifying and obtaining the equipment needed for an investigation is part of preplanning. Required equipment may include:

Large equipment for lifting ceilings or walls.
Equipment for removing debris or evidence.
Laborers.
Small hand tools.

Human resources needed for an investigation may be obtained by retaining a construction company. Some construction companies are equipped to provide this type of assistance.

Transportation may be an issue at some large sites. Parties may require transportation:

From a remote parking area to the site.
To and from a checkpoint.
From the scene to an evidence-storage facility.

Transportation planning should give special consideration to large evidence items.

Decontamination arrangements may include:

An area positioned upwind.
A changing area.
Washing facilities.
Showers.

Other logistical considerations include:

Communication among parties at the site.
Lighting or spotlights.
Ice and snow removal.
Heating the scene.
Break and shelter areas.
Food and water.

Part 4 – Public-Sector Considerations and Public–Private Coordination

Public-Sector Considerations in the Complex Investigation

Public-sector investigators may participate in large scenes involving investigators from numerous agencies, including:

Fire departments.
Police departments.
Multijurisdictional investigative teams.
Coroner or medical examiner personnel.
Building officials.
Local officials.
State officials.
Federal officials.

Many of the same management factors that apply to private multiparty investigations also apply to public-sector investigations. However, public agencies may not experience the same tensions that can arise among private entities with different interests and needs.

Many of the same logistical needs may arise regarding:

Group communications.
Safety notifications.
Logistics.
Sharing of resources.

The same planning and management principles used in other complex investigations can provide a template for the public investigator responsible for managing a large scene.

Public–Private Coordination

In most jurisdictions, public-sector investigators control a scene immediately after the fire. They are charged by statute with investigating fires and determining whether crimes were committed. They may need to retain control of the scene until that determination is made.

Private investigative interests should still be considered by public-sector agencies, particularly when criminal activity has been ruled out or is not strongly suspected.

In some jurisdictions, fire codes and other regulations require the fire chief or another official to determine the cause of all fires. Even under those circumstances, serious consideration should be given to:

Bringing private-sector investigators into the investigation.
Returning the scene to the person controlling the property so a private investigation can proceed.

Reasons for Relinquishing a Complex Fire Scene

A public fire agency may decide to relinquish a complex scene for several reasons.

A complete complex-fire investigation may require substantial expenditures for:

Experts working at the scene.
Laboratory testing.
Engineering testing.
Heavy equipment for removing and disposing of building components.

A public agency may be unwilling or unable to afford these expenses or commit investigators to a forensic investigation lasting several days or weeks.

Complex scenes may also require the collection and transportation of numerous noncriminal evidence items. Most public agencies are not equipped to transport or store noncriminal fire evidence.

Public officials should also recognize that private parties have a strong interest in investigating fires and determining their causes. Large-fire losses may be catastrophic, and litigation may be likely. Determining the party responsible in a civil case, including negligence or product-liability cases, is important both to the parties and insurers involved and to society as a whole.

In many cases, it is appropriate to involve private parties and allow them to examine the scene and evidence.

Public Examination Followed by Private Control

A common method of public–private coordination is for the public agency to conduct its initial scene examination and then relinquish the scene.

When no significant public interest remains and a criminal case is unlikely, the agency may leave the scene and transfer it to:

The person responsible for the property.
The responsible person’s insurance carrier.
An investigator representing the responsible person or insurance carrier.

If an insurance carrier or investigator has not yet arrived, the responsible person should be instructed to:

Protect the scene.
Avoid disturbing or moving items within the fire area.

These measures allow the insurer and/or investigators to examine the scene effectively when they arrive.

The public-sector investigator should understand that ending the scene examination and leaving the site may affect the agency’s future ability to:

Reenter the scene.
Maintain a chain of custody for evidence.

When criminal charges are unlikely, the public agency will often determine that it is safe to relinquish control.

If the fire’s origin and cause remain undetermined when the scene is transferred, public investigators should:

Record the interim conclusion in their reports.
Make the conclusion subject to further evidence.
Allow final conclusions to come from other expert parties.

Findings developed by private experts can always be incorporated into the public agency’s eventual conclusions concerning the fire.

Continued Public Participation After Transfer

A public agency may relinquish control while leaving one or more investigators at the site to continue participating in or observing the private investigation.

This arrangement should be based on:

An understanding between the parties.
An agreement from the person responsible for the property.

If evidence of criminal activity is later uncovered, private parties must:

Notify the public agency.
Permit the public agency to resume control of the scene.
Allow the public agency to address the criminal issue.

Public Control with Private Participation

A public agency managing a complex investigation may remain at the scene and retain control while inviting private entities to observe or participate.

This approach can:

Ensure that all interests are represented at the scene.
Reduce complaints that evidence was altered or spoiled before private parties could conduct their own examinations.

Scene integrity is preserved when:

The actions of all personnel are documented.
Evidence is identified and collected appropriately.
Public personnel decide which role each party will have during the examination.

For example, public investigators may lead and perform the scene work while private investigators:

Observe and photograph the process.
Observe and photograph the removal of debris and evidence.

This method may be appropriate when criminal activity remains a significant possibility.

Parallel Public and Private Investigations

When there is no strong indication of criminal activity, public and private investigations may proceed in parallel. Both public and private investigators perform tasks and observe each other’s findings.

This approach requires a plan ensuring that:

Both sides remain independent.
Neither side takes instructions from the other.

The public entity may continue to act as the party in charge. A site plan for safety or other topics may be developed.

The parties should agree in advance on:

How evidence will be collected.
How evidence will be stored.

Alteration and Removal of Evidence

Public investigators should attempt to avoid altering evidence without considering the interests of other parties.

NFPA 921 recognizes that normal scene sifting and debris removal do not constitute spoliation of evidence. Even so, when evidence must be altered, public investigators should consider involving other interested parties.

Public investigators should document any alteration or removal of evidence according to recognized standards and processes.

Public investigators should attempt to avoid altering evidence without considering the interests of other parties.

Public investigators should document any alteration or removal of evidence according to recognized standards and processes.

Part 5 – Fatal Fire and Explosion Scene Investigation, Documentation, Evidence, and Body Removal

Fire and Explosion Deaths and Injuries

When a fire or explosion results in death or serious injury, the investigation becomes more complex and involved. Public-sector fire investigators experience greater responsibility and scrutiny from:

Their agency.
Other agencies.
Victims’ families.
The press.

Correct procedures should be followed from the beginning. Every fire or explosion involving serious injury should receive a full investigation.

Investigators should:

Preplan for the possibility of a fatal fire within their jurisdiction.
Be prepared to call on other team members and professionals needed to conduct the investigation.

A fatal fire or explosion requires a two-part investigation:

Determining the origin and cause of the fire or explosion.
Determining the cause and manner of death.

The body of the victim is the most important piece of evidence in determining the cause and manner of death. It must be protected and treated properly, and the correct investigative steps must be followed.

Fire Suppression

Firefighters responding to a fatal fire scene must be made aware of the importance of preserving the scene as much as possible while still performing appropriate fire-suppression operations and rescuing potentially viable victims.

Hose streams and overhaul activities can damage:

A body.
Other fragile evidence.

When a victim is discovered and there is no question that the person is deceased, every effort should be made to leave the body in its original location. A fire or explosion victim should receive the same consideration as a murder victim at another crime scene.

In the uncommon situation where leaving the body in place would result in further damage, the body may be moved if permitted by law. The purpose of moving it is to preserve it for further examination. Before it is moved:

The body should be fully photographed.
Everything beneath and around the body should be photographed.
The body’s physical location should be marked so its exact location can be recalled during debris removal.

Marking the location allows the area to be examined further for evidence.

A body is a piece of evidence and should always be treated as such.

Agency Notification

When a death occurs, most jurisdictions legally require notification of certain parties. These parties may include:

Law enforcement.
Medical examiners.
Coroners.
Other designated personnel or agencies.

Fire investigators must understand the applicable requirements and notify the appropriate personnel when a fire death occurs.

Ideally, the investigator should establish contacts and working relationships with these personnel and agencies before a fatal fire event occurs.

Documentation

The body and its surrounding area should be photographed:

Before the scene is disturbed.
Throughout debris removal.
Throughout body removal.

Photographs should document:

The body’s relationship to surrounding items.
The body’s condition.
Fire or explosion patterns.
Other physical characteristics of the scene.
Possible fire patterns or blast effects on the body.

All debris around, beneath, and on top of the body should be examined for evidence related to the death.

The body should also be photographed:

When it is placed in the body bag.
While it is being moved.
When it is removed from the body bag.
While clothing is being removed.

Close-up and scale photographs should be taken of burns and other injuries. The location where the body was resting at the fire scene should also be photographed.

If the deceased victim must be removed quickly, the investigator should still take a rapid series of photographs whenever possible.

When a victim’s body remains at the scene but has been moved from its original position, the investigator should document as much of the body’s original location as possible, including:

Patterns on the body.
Items around the body.
The path along which the body was moved.

When the body has already been removed before the investigator arrives, the investigator may reconstruct its location for analysis. One method is to knot one corner of a sheet and position the sheet where the body rested, using the knot to represent the head.

Scene documentation should include sketches and diagrams recording:

The scene’s physical dimensions.
The contents of the scene.
Measurements showing the body’s location.

Figure 12-3 — Body-Location Diagram

A body-location diagram can record the body’s position and its measured relationship to surrounding features such as walls, a dresser, a chair, and a bed. Measurements around the head, arms, torso, and feet establish the body’s exact position within the room.

A skeleton outline of the body may be used for reference when photographs of the victim are considered inadmissible in court because of their shocking or gruesome nature.

A “victim sketch” may also be used to record burns and other injuries.

When examining and diagramming a fatal scene, investigators should consider evidence documenting the victim’s activity during the incident, including evidence that the victim:

Started the fire.
Attempted to fight the fire.
Attempted to flee the fire.
Took refuge from the fire.
Attempted to rescue people, animals, or property.

Tip: Fatal fires create a risk of exposure to biohazard materials in addition to the safety concerns normally present at fire scenes. Appropriate PPE, decontamination, and disposal procedures should be included in the investigation plan.

Scene Examination and Evidence

Fire and explosion investigations are often conducted by teams. When a death is involved, the investigative team may expand to include:

A police detective.
A medical examiner or coroner.
Forensic laboratory personnel.
A forensic pathologist.

When a body is badly burned, the expertise of a forensic anthropologist and a forensic dentist, or odontologist, may be required.

Although much of the investigative attention may focus on the place where the body was found, important evidence may be located some distance away because of:

The victim’s activities.
Environmental conditions.
Fire-suppression efforts.

The area through which the victim may have traveled during the incident is important for examination. Areas within the victim’s arm’s reach are especially important.

The size of the scene may require more than one investigator. One investigator may focus on the death investigation while another determines:

The area of fire origin.
The point of origin.
The cause of the fire.

A grid system may be used to divide the scene into sections. Each grid section should be:

Examined.
Documented.
Checked for evidence that must be identified.

When the scene does not support a grid search, a spiral pattern or another search method may be appropriate. Any search method used should provide overlap so the scene receives complete coverage.

Figure 12-4 — Scene Sectors

Marking a room into sectors helps ensure complete investigative coverage. Each sector can be examined separately while overlapping adjacent areas.

The area should be examined for all potential evidence. Small evidence items may be located by:

Removing debris from one section at a time.
Carefully screening the debris.
Using multiple screens with different mesh sizes.

Removal of Body

Removal of a deceased fire victim should follow the method prescribed by the coroner, medical examiner (ME), or another official with authority.

In most jurisdictions, the body itself should not be disturbed without the coroner’s or ME’s approval. Although the fire investigator may examine the victim’s surroundings and perform most fire-investigation tasks, activities directly involving the body should be avoided without consulting and involving the coroner or ME.

Activities requiring such consultation may include removing:

Fire debris resting on top of the victim.
Building components resting on top of the victim.

To facilitate removal of the body, the coroner or ME and the fire investigator may determine that fire debris present on the victim must be removed.

Removal of this debris must be conducted:

Gently and carefully.
With a complete examination of the debris being removed.
With full documentation of the debris being removed.

Only debris that is not attached to the body should be removed in this manner. Material adhering to the body should remain attached. Any item falling from the body during removal should be collected with the victim.

After the body is removed:

Examine the area where it rested for potential evidence.
Note anything in the victim’s hands.
Photograph the scene and the items uncovered throughout the excavation and recovery process.
Treat the body respectfully and as evidence.
Preserve the chain of custody.
Avoid cross-contamination.

Tip: A body found at a fire or explosion scene must be treated as evidence. The chain of custody must be maintained, cross-contamination must be avoided, and material attached to the body must remain intact for further examination.

Tip: Document the path and manner by which the victim was removed from the structure because accidental trauma may occur to the victim’s body during removal. Interview the personnel who performed the removal and document their responses.

Clothing and Possible Ignitable-Liquid Residue

A victim’s clothing may contain ignitable-liquid residue. Whenever possible, the clothing should be preserved for its evidentiary value.

When the body was transported away from the scene before investigators arrived, investigators should contact the coroner or ME and request preservation of:

The victim’s clothing.
Other evidence found on the victim.

Victim clothing to be tested for ignitable-liquid residue must be promptly packaged like other fire debris. This usually means that a fire investigator or another person trained in fire-debris collection should collect it.

Recovery of Burned or Fragmented Remains

When a body has been badly burned or fragmented by fire or explosion, the area should be searched carefully for all human remains, regardless of size. Recovered remains should be transferred to the coroner or ME.

Burned bones and tissue can blend with fire debris and may be overlooked. A forensic anthropologist is often used at fire scenes to help ensure that all remains are identified and collected.

Specialists can also advise how to preserve bones and bodies that are discovered during the removal process.

Figure 12-5 — Identification of Remains

It may be necessary to determine whether bones recovered at the scene are animal or human.

When animals die in a fire, it may be useful to conduct a postmortem examination on them to gather additional information.

Burned bones and tissue can blend with fire debris and may be overlooked. A forensic anthropologist is often used at fire scenes to help ensure that all remains are identified and collected.

Specialists can also advise how to preserve bones and bodies that are discovered during the removal process.

Figure 12-5 — Identification of Remains

It may be difficult to determine at the scene whether recovered remains are animal or human.

When it is necessary to determine whether recovered bones are animal or human, a postmortem examination may provide additional information.

Part 6 – Autopsy, Pathological and Toxicological Examination, Fire Effects, and Postmortem Changes

Autopsy and Pathological/Toxicological Examination

Whenever a fire or explosion occurs and a body is discovered at the incident site, a competent forensic pathologist should perform an autopsy to determine the cause of death.

When possible, a fire investigator should attend the autopsy to:

Point out specific evidence.
Take custody of evidence as it is recovered.
Share important investigative information with the medical personnel performing the tests.

Items that may be recovered for future analysis include:

Clothing and personal effects.
Bullet remains.
Chemical residues from ignitable liquids.
Tissue and body fluids.
Other physical evidence.

When ignitable liquids are suspected, the evidence must be handled in a specific manner. In most cases, it is best collected by a trained fire investigator.

Fire investigators should become acquainted with coroners’ staff and medical examiners in their area and establish an investigative understanding with them. As part of this relationship, investigators may receive permission to:

Attend examinations.
Observe other procedures.
Perform photographic documentation.

Even when investigators cannot attend the autopsy, they should try to ensure that the pathologist performs the examinations normally required in a fire case and any tests related to issues specific to that case.

Tests and examinations normally included in a fire-related autopsy include:

Blood: Determine levels of carboxyhemoglobin (COHb), hydrogen cyanide (HCN) concentration, drugs, alcohol, or poisons.
Internal tissue: Determine levels of volatile hydrocarbons, drugs, or poisons.
Stomach: Examine the contents, including the presence or absence of soot.
Airways: Examine for the effects of the fire.
Internal body temperature: Assist in establishing the time and mechanism of death.
X-rays: Assist in identifying the victim, identifying injuries, and locating foreign objects within the body.
Clothing or personal effects: Assist with identification or determine whether ignitable liquids are present.
Recovery of foreign objects in or on the body: Recover bullets, knife parts, explosive-device components, and other items.
Sexual-assault evidence: Provide possible evidence of other crimes, identify an aggressor, and establish a possible motive for setting a fire.
Documentation by photography and sketching: Record injuries and burns to the body and evidence recovered from the body.

Figure 12-6 — Fire Investigation Data Sheet: Body Diagram

A body diagram can be used to mark and document injuries to a deceased victim of a fire or explosion. The chart provides front, back, side, and top views of the body, along with spaces for the examiner’s signature and the date.

X-Rays

One of the first steps in examining a body is to perform full-body X-rays.

X-rays help identify foreign matter within the body, such as:

A bullet.
A knife tip.

Foreign matter may provide evidence concerning the fire incident or crimes committed against the victim.

X-rays may also help identify the victim through:

A prior bone fracture.
A surgical metal implant.
Dental remains.

These findings can be compared with a known set of X-rays.

Full-body imaging may also detect newly broken bones associated with the fire incident or crimes committed against the victim.

Figure 12-7 — Foreign Objects Revealed by X-Ray

A full-body X-ray can reveal a bullet within the pelvic area of a fire victim.

Tip: Depending on the jurisdiction, X-ray examinations may not be performed routinely on victims. The investigator may have to request specifically that the procedure be conducted.

Carbon Monoxide and Other Toxic Products

Testing blood and tissue for carbon monoxide (CO) is one of the easiest and most common medical tests performed on fire or explosion victims.

Testing often reveals information concerning the cause and sequence of events and should be conducted whenever possible.

Carbon monoxide is absorbed into the blood and tissue through breathing. It may produce a cherry-pink coloration of the skin. This coloration may not be visible:

On victims with dark skin.
On victims heavily covered with soot.

Cherry-pink coloration may appear in several areas, including:

The lips.
Blood that pooled within the body through postmortem lividity.

The medical examination should also search for other toxic products. Products of combustion that may be detected in blood and tissue include:

Hydrogen cyanide.
Hydrogen chloride.

The same body samples may also reveal:

Medical drugs.
Illicit drugs.
Alcohol levels.

This information may help investigators interpret the victim’s ability to cope with the events occurring during the incident.

Gas chromatography and liquid chromatography are two techniques used to determine the levels of various substances within the body.

Soot

The examination should identify and document smoke and soot in:

The breathing passages.
The stomach.

Soot may be present on the body’s exterior and in and around the nose and mouth. These deposits do not necessarily prove that the victim was breathing during the fire.

Soot in internal airways, such as the trachea and lungs, is generally consistent with a victim breathing in a smoke-filled environment. Soot in the stomach is also consistent with breathing during the fire.

The presence or absence of soot in the internal airways may help establish a timeline for the fire and the victim’s death.

An absence of soot in the internal airways may suggest that the victim was not breathing during the fire because the victim:

Died before the fire.
Died in a different location.

Tip: A fire victim may have been impaired by alcohol or drugs in addition to carbon monoxide, hydrogen cyanide, and other fire gases. The victim’s total impairment may therefore result from a combination of the prefire impairment and exposure to fire toxins.

Burns

Burns to the body should be identified and documented. Burns may occur before or after the victim’s death.

Blistering of the skin associated with a second-degree burn can occur to a limited degree after death.

The effects of heat include:

The skin and muscle tissue losing water.
Noticeable muscle shrinkage.
Muscle contraction.

This contraction produces a fixed attitude in the victim known as the pugilistic attitude. It is a boxer-type stance visible in the hands and arms. In later stages of exposure, the same muscle contraction may occur in the legs.

The pugilistic attitude has sometimes been interpreted incorrectly as evidence that the victim adopted a defensive stance to ward off blows to the chest and head. It is caused by heat-related muscle contraction and can even fracture bones in the arms or legs.

Blood

During examination of the body, blood or suspected blood located outside the body should be noted and documented when found:

On clothing.
On furnishings.
Elsewhere at the scene.

The locations of suspected blood should be correlated with information from the scene and the medical examiner. This helps determine whether the blood resulted from:

The fire event.
Non-fire-related trauma.

Consumption of the Body by Fire

The body may form part of the fuel load at a fire scene. Investigators should examine the burn patterns and extent of burns on a victim in the same manner as other fuel items to determine:

Whether fire patterns are present.
How those patterns correlate with other patterns in the surrounding area.

When exposed to sufficient heat, the body may be consumed to some degree.

Although skin and muscle tissue are considered poor fuels, they dehydrate during the fire and are consumed over time. Bones:

Shrink.
Change color.
Eventually fracture.

Body fat is combustible. Under some conditions, body fat may be absorbed by a wicking material, such as cotton clothing, and serve as a fuel source for a small but concentrated flame.

The energy from this flame may be insufficient to ignite adjacent combustible materials. However, it can consume areas of the body where the concentration of fat is greater, such as the torso.

Figure 12-8 — The Body as Fuel and Evidence

The body is both part of the fuel load and a piece of evidence and must be examined accordingly.

Heat may fracture or crack the skull, most often along the suture lines. Gunshots and other trauma can also produce fractures. A skilled forensic pathologist or anthropologist may therefore be required to make the final determination concerning the cause of a fracture.

No credible evidence substantiates the theory of spontaneous human combustion. An investigator should not rely on this theory as a fire cause.

Postmortem Changes

After death, several physical changes begin to occur within the body.

Lividity

Lividity is the pooling of blood in the lower elevations of the body caused by the effects of gravity.

Lividity becomes fixed within the body 6 to 9 hours after death. If the body is moved before lividity becomes fixed, the pooling of blood can change.

Figure 12-9 — Postmortem Blood Pooling

In the hours after death, blood pools in the lower elevations of the body. This pooling may help indicate how long the person has been deceased.

Rigor Mortis

Rigor mortis begins to stiffen the body’s joints a few hours after death.

The effects of rigor mortis begin to leave the body after approximately 12 to 24 hours, proceeding from the body’s extremities back toward the torso and head.

The onset of rigor mortis may be accelerated by:

Extreme muscular activity before death.
Elevated surrounding temperatures.

Forensic pathologists may use the status of rigor mortis to estimate the time of death.

Rigor mortis should not be confused with the rigidity of the body’s muscles caused by exposure to heat.

Postmortem Timeline and Environmental Conditions

The rate at which postmortem changes occur may be affected by several factors, including:

Time.
Climate conditions.

Whenever possible, investigators should create a victim timeline that includes:

Time of body discovery.
Time of body removal.
Transportation times.
Time of examination.
Environmental conditions.
Temperature during storage.
Method of storage.

This information may help interpret medical data obtained through pathological and toxicological findings.

The rate at which postmortem changes occur may be affected by environmental factors such as:

Time.
Climate conditions.
Temperature.
Humidity.

Whenever possible, investigators should create a victim timeline that includes:

Time of body discovery.
Time of body removal.
Transportation times.
Time of examination.
Environmental conditions.
Temperature during storage.
Method of storage.

This information may help interpret medical data obtained through pathological and toxicological findings.

Part 7 – Death Investigation, Victim Identification, Combustion Products, and Cause and Manner of Death

Issues for Fire Investigators in Death Investigation

Issues that a fire investigator may have to address during a fatal fire investigation include:

Recognizing human remains.
Identifying a fire victim.
Investigating the victim’s prefire activities.
Understanding the cause and manner of death.

Remains and Victim Identification

A fire investigator and forensic personnel may initially have difficulty determining whether a badly damaged body or body part is human or animal. The remains of some large animals may resemble human remains.

A trained anthropologist or another expert may be required to determine with certainty whether the remains are human.

The coroner or medical examiner (ME) normally identifies a human fire victim. Identification information is also important to the fire investigator, who may be asked to assist.

When the body has experienced only moderate heat and fire effects, visual identification may be possible. However:

Facial skin may tighten and alter the victim’s appearance.
Hair color may change.

Clothing and personal effects may provide circumstantial identification evidence.

Fingerprints may also identify the victim. The pugilistic attitude causes the victim’s fingers to curl into the palm, which may protect the fingertips enough to permit fingerprinting and comparison.

Other identification methods include:

Tattoos.
Dental X-rays compared with known X-rays of the victim.
Reconstruction and comparison of recovered dental remains.
Surgical implants and other medical devices.
DNA comparison with a family member.

The head and teeth are often well preserved in a fire. When destruction of the head is extensive, dental remains should be located, recovered, reconstructed, and compared.

Advances in DNA-related technology have improved its usefulness for victim identification. In some cases, comparing the victim’s DNA with the DNA of a family member may be necessary.

Identification of Children and Infants

The bodies of children and infants present special identification difficulties because their skeletal structures are less developed than those of adults.

It may be impossible to determine the sex of a child victim using skeletal remains alone.

Children also have:

Less skeletal development.
Less tissue mass.

In an extreme fire, a child’s skeleton may be fully consumed, leaving very few remains. Investigators should search especially carefully when child remains may be present.

Victim Activity

When determining the cause and manner of death, investigators should examine and interpret evidence concerning the victim’s activities before and during the fire.

Evidence that may provide information about victim activity includes:

The physical location of the body, such as a body found in a bed.
The victim’s clothing.
Items located around or near the body, such as a fire extinguisher.

Patterns of damage to the victim’s clothing and body should be interpreted within the context of the entire scene. Investigators should closely examine inconsistencies.

Burn patterns on the body or clothing may indicate that the victim:

Attempted to extinguish the fire.
Attempted to escape.

Other relevant evidence may include smoking materials or food being prepared for cooking.

Understanding the victim’s prefire physical abilities may help explain the victim’s movement or lack of movement.

Interviews with people associated with the victim may help determine the victim’s activities before death, including:

When the victim was last seen.
When the victim was last heard.

Combustion Products and Their Effects

Many products of the combustion process can affect the victim of a fire or explosion.

These products may include:

Carbon monoxide.
Carbon dioxide.
Nitrogen oxides.
Halogen acids.
Hydrogen cyanide.
Acrolein.
Benzene.
Particulates such as soot and ash.
Aerosols.

Inhaling these products or allowing them to contact the skin directly can produce various effects on the human body.

Carbon Monoxide

Carbon monoxide (CO) is a product of all fires and is generated by incomplete combustion of fuel.

The amount of CO produced during a fire depends on:

The completeness of combustion.
The type of fuel package.

Carbon monoxide acts as both an anesthetic and an asphyxiant. Inhalation can cause dizziness and confusion during early exposure to concentrations in the range of 1,000 to 1,500 ppm. Exposure at these concentrations can result in death in as little as one hour.

After inhalation, CO binds with hemoglobin in the blood and forms carboxyhemoglobin (COHb).

Because CO binds with hemoglobin in the blood much more readily than oxygen does, dangerous COHb levels can develop even when the concentration of CO in the fire environment is relatively low.

When a person is removed from a CO-exposure environment, CO levels within the blood begin to decrease. This process can take many hours.

CO remains stable in the body and can therefore be tested several hours after death.

As a general rule:

COHb levels of 50 percent or greater are considered fatal.
Death may occur in some cases at concentrations as low as 20 percent.
When COHb is below 20 percent, death was most likely caused by another factor, such as thermal injury or physical trauma.
A COHb level of 40 percent or greater indicates that the toxic effects of CO, either alone or combined with other factors, likely contributed to the cause of death.

Most victims affected by fatal CO levels die in areas remote from the room of fire origin. Studies have found that at least 60 percent of fire victims die from CO poisoning.

Non-fire-related factors may also produce elevated CO concentrations. Smokers and people exposed to automobile exhaust or coal-mine environments may have background CO levels of 4 to 10 percent.

Estimating Carbon Monoxide Exposure

The Coburn–Forster–Kane (CFK) equation or the Stewart equation can be used to estimate the amount of CO inhaled by a victim.

The CFK equation uses:

The concentration of CO produced by the fire over time.
The victim’s weight.
The volume of air exchanged through breathing per minute.

This information can produce a range of COHb values associated with the average exposure to CO. The estimated range can then be compared with a known COHb value determined during autopsy.

The Stewart equation estimates the inhaled CO using the relationship among:

COHb.
Inhaled CO concentration.
Respiratory minute volume.
Exposure duration.

Detailed explanations of the CFK and Stewart equations are provided in NFPA 921, Guide for Fire and Explosion Investigations, Section 24.10.8.2.1–24.10.8.2.4.

Cyanide

Hydrogen cyanide (HCN) is another toxicant produced during combustion.

HCN is a by-product of burning common household items containing materials such as:

Wool.
Nylon.
Various plastics.

HCN, either by itself or combined with other toxic gases, can incapacitate victims or cause death.

HCN is absorbed rapidly into the blood through respiration—more rapidly than CO—which helps explain its rapidly lethal effects.

Cyanide affects the body’s ability to use oxygen rather than binding with oxygen in the manner of CO.

Cyanide is most commonly measured in blood, but it can also be measured in tissue samples from:

The liver.
The brain.
The lungs.
The kidneys.

Unlike CO, HCN does not always remain stable in tissues. The distribution of cyanide among the organs may also vary.

The stability of postmortem samples depends on:

Time.
Storage temperature.
Preservation methods.

Other Toxic Gases

A wide range of fuels may be present in an ordinary setting, producing a similarly wide range of gases during a fire. Many of these gases cause irritation and swelling or are toxic.

Two gases commonly encountered in fires are hydrogen chloride and acrolein.

Hydrogen chloride is released when polyvinyl plastics burn.
Acrolein is produced by the combustion of wood and cellulosic products.

These and other combustion by-products should be considered when assessing a victim’s ability to act and move during a fire.

Soot and Smoke Exposure

Most fuels produce smoke and soot when burned, although the amount varies by fuel.

Hot soot particles may cause thermal injuries leading to edema, or swelling.

Soot may also:

Transport toxins into the body.
Block the victim’s airways in extreme cases.

Liquid mists of pyrolysis products are often acidic aerosols. When inhaled, they may cause systemic failure.

Sublethal Inhalation Exposure

Narcotic gases such as CO and HCN, along with the effects of hypoxia, may limit the mental and psychomotor abilities of an exposed person.

Other smoke by-products and irritants may:

Interfere with respiration.
Irritate the eyes.
Impair vision.
Reduce the ability to see.

The levels of these combustion by-products in the body begin to decrease when the person withdraws from the affected area.

Low concentrations of irritant gases may alert people to a fire. At greater concentrations, these gases can cause enough irritation to obscure vision or alter behavior.

After a fire, respiratory edema or inflammation may develop.

Smoke can obstruct vision and slow escape travel. The extent to which smoke and other effects influence a victim’s escape attempt may depend on:

Prior knowledge of the building or area.
The extent of smoke and heat conditions.
Obstructions to travel.
The condition and availability of exits.

Hypoxia

Hypoxia results when a victim breathes in an environment with reduced oxygen.

As a fire burns in a confined area, it depletes oxygen from the air.

As oxygen decreases from its normal starting concentration of 21 percent to approximately 15 to 10 percent:

Respiration gradually increases.
Disorientation follows.

Oxygen concentrations below 10 percent cause unconsciousness followed by the cessation of breathing.

Blood tests conducted on a hypoxia victim after death do not provide reliable information because oxygen and carbon-dioxide levels begin to change after death.

Thermal Effects

Thermal effects from a fire can cause death or injury.

In hyperthermia, the body’s temperature becomes greatly elevated. Depending on exposure time and temperature, hyperthermia may be classified as:

Simple hyperthermia.
Acute hyperthermia.

Simple Hyperthermia

Simple hyperthermia is caused by extended exposure—15 minutes or longer—to hot environments.

Over time, the body’s temperature increases. Internal temperatures greater than 109°F (43°C) can become fatal within a few minutes.

Humidity and moisture further reduce the body’s ability to release excess heat.

Acute Hyperthermia

Acute hyperthermia results from short exposure to high heat levels.

Thermal burns also occur, but the cause of death is related to the elevated body temperature.

Inhaling hot gases and various toxic gases can produce edema and inflammation in the airway. The effects of hot gases are generally accompanied by:

Facial burns.
Singed facial hair.

Hot-gas inhalation may also produce a physical blockage of the airway.

Inhaling soot may introduce toxic compounds into the body, cause thermal injury, or physically block the airway.

Skin Burns

Pain occurs when the skin reaches a temperature of approximately 110°F (45°C).

Thermal energy may transfer to the skin through:

Conduction.
Convection.
Radiation.

Conductive heat may transfer through clothing even when the clothing itself does not display visible signs of heat exposure.

When skin is exposed to convective heat through air temperatures greater than 120°F (49°C), pain and injury occur.

As radiant heat increases, the heat flux increases and tissue damage occurs more rapidly.

Inhalation of Hot Gases

Inhaling hot gases may result in death or injury. Chemical irritants can cause similar effects.

Hot-gas inhalation is often accompanied by:

Burns to the skin.
Burned facial hair.

Animal research found that hot gases at 932°F (500°C) produced larynx and trachea damage, while steam at 212°F (100°C) produced burns deep within the lungs.

Cause and Manner of Death

After the autopsy and other investigative steps are completed, the coroner or medical examiner provides an opinion concerning the cause and manner of the victim’s death.

The cause of death is the actual disease or injury that produced the death. Examples include:

Smoke inhalation.
Burns.
A gunshot wound.

The manner of death describes how the injury or disease resulted in death.

The manner of death is generally classified in one of five ways:

Accidental.
Homicidal.
Suicidal.
Natural.
Undetermined.

After the autopsy and other investigative steps are completed, the coroner or medical examiner provides an opinion concerning the cause and manner of the victim’s death.

The cause of death is the actual disease or injury that produced the death. Examples include:

Smoke inhalation.
Burns.
A gunshot wound.

The manner of death describes how the injury or disease resulted in death.

The manner of death is generally classified in one of five ways:

Accidental.
Homicidal.
Suicidal.
Natural.
Undetermined.

Part 8 – Fire and Explosion Injuries, Medical Evidence, and Injury Documentation

Fire and Explosion Injuries

A fire or explosion victim may die long after the incident has ended.

Fires and explosions involving serious injuries should be investigated in the same manner as fatal investigations. A full investigation will then already exist if the victim later dies.

When a victim has extensive injuries, investigators may be unable to obtain a statement for an extended period. Investigators should continue gathering evidence through normal methods and should not delay other investigative work while waiting to interview the victim.

Other sources of information may include:

Surveillance footage.
Interviews with bystanders.

The nature of the victim’s injuries should be documented promptly because the injuries may begin to heal and change in appearance.

Some jurisdictions require medical personnel to report burn injuries in a manner similar to gunshot wounds. These reporting laws may:

Assist in identifying victims of abuse and assault.
Identify a person burned while starting a fire.

Investigators should be aware of the laws applicable within their jurisdiction.

Examination and Documentation of Injury Event

Examination of a serious-injury scene requires much of the same work as examination of a fatal scene.

Physical evidence may indicate:

The victim’s activities.
The source of the victim’s injuries.

Relevant evidence may include:

Blood.
Clothing.
Burned skin.

Indicators that may help establish the victim’s location include:

Soot lines of demarcation.
Protected areas.

When reliable evidence of the victim’s position is found, that position should be diagrammed with the same level of detail used for a fatal fire.

Emergency or hospital personnel may remove the victim’s clothing. It should be collected as soon as possible to prevent its loss.

Clothing may:

Contain physical evidence in the pockets.
Have acted as a fuel source during the fire.

When clothing must be tested for ignitable-liquid residue, it must be collected like fire debris so that any ignitable liquid does not evaporate.

Medical Evidence

Whenever possible, investigators should document:

The treatment provided to the fire victim during transport.
The treatment provided at the hospital.
The time of toxicological testing.
The results of toxicological testing.

A fire investigator may need to understand the medical factors involved in the victim’s injuries.

Burns

Medical reports use several terms to document evidence associated with burns.

Degree of Burn

Burn injuries should be documented and assessed according to their degree:

First-degree burn: Reddening of the skin; also called a superficial burn.
Second-degree burn: Blistering of the skin; also called a partial-thickness burn.
Third-degree burn: Full-thickness damage to the skin; also called a full-thickness burn.
Fourth-degree burn: Damage to the underlying tissue and charring of the tissue.

Body Area and Distribution

The medical community estimates burn damage using the “rule of nines.”

The body is divided into segments representing percentages of the total body area. The percentages for injured portions are added together to estimate how much of the body was affected by the burn injury.

The percentage of body area burned is sometimes used to predict survivability.

Resources concerning body areas and burn survivability include Tables 24.8.1.3 and 24.8.1.4 in NFPA 921.

Figure 12-10 — Rule of Nines

The rule of nines provides a quick estimate of the amount of body surface area that has been burned.

The body-area percentages vary with age:

Infant: Head, 18 percent; front torso, 18 percent; back torso, 18 percent; each arm, 9 percent; each leg, 13.5 percent; genital area, 1 percent.
Child: Head, 12 percent; front torso, 18 percent; back torso, 18 percent; each arm, 9 percent; each leg, 16.5 percent; genital area, 1 percent.
Adult: Head, 9 percent; front torso, 18 percent; back torso, 18 percent; each arm, 9 percent; each leg, 18 percent; genital area, 1 percent.

Mechanism of Burn Injury

The cause of a burn—whether scalding, chemical exposure, hot gases, or flames—may not be distinguishable by appearance alone.

There is a direct relationship between burn formation and radiant heat flux.

For example:

A radiant heat flux of 2 kW/m² produces pain after 30 seconds without blistering the skin.
A heat flux of 10 kW/m² produces pain after 5 seconds and blisters the skin in 12 seconds.

Conducted heat brings the skin into direct contact with the heat source. It is therefore more dangerous than heat transferred through radiation or convection.

Conductive heat may transfer through clothing and burn the skin even when the heat source does not burn the fabric.

Documentation of Thermal Injury

As with all elements of an investigation, thermal injuries should be thoroughly documented.

Documentation may include:

Sketches.
Color photographs.

When possible, documentation should be completed before treatment or healing changes the appearance of the wounds.

Inhalation

Fire produces various by-products that can affect an exposed person.

Testing is needed to determine the levels of these by-products in the body and to understand:

The injured person’s actions.
The environment in which the person was exposed.

The percentage of CO eliminated from the body is directly related to the amount of oxygen available to the victim.

When a victim with elevated CO levels is placed in a normal atmosphere, CO decreases by approximately half in about five hours.

More precisely:

The half-life of COHb in a normal environment is approximately 250 to 320 minutes.
When the victim receives 100 percent oxygen, the COHb half-life decreases to approximately 60 to 90 minutes.

Understanding these changes is important when interpreting COHb levels in people who received treatment.

Hospital Tests and Documentation

When a victim with a fire-related injury is admitted to a hospital, a blood sample should be obtained and analyzed for:

COHb level.
HCN concentration.
Blood alcohol level.
Drugs.
Other relevant substances.

The blood sample should be obtained as soon as possible because most marker levels begin to decrease with time and treatment.

Access to Medical Evidence

Many federal and state laws affect an investigator’s ability to obtain a victim’s medical records.

Depending on the circumstances, medical records may be obtained:

With the victim’s consent.
Through a legal method, such as a court order.

Knowledge of laws related to medical records is helpful in this process.

The victim’s previous medical history may identify conditions affecting the person’s ability to:

Comprehend the danger.
Move about.
Detect the danger of a fire.

Medical history may also provide evidence that the victim died before the fire, such as from a heart attack.

Explosion-Related Injuries

The location and distribution of injuries on an explosion victim’s body may indicate the victim’s location and activity when the explosion occurred.

Injury patterns may also help establish the location, orientation, energy, and function of the exploding mechanism or device.

Explosion-related injuries are classified into four groups according to the explosion effect that caused them:

Blast-pressure injuries.
Shrapnel injuries.
Thermal injuries.
Seismic injuries.

Blast-Pressure Injuries

Blast-pressure injuries result from the concussion effects of an explosion.

Damage to internal organs is not uncommon and depends on the strength of the blast pressure.

The blast-pressure wave may propel the victim into objects and produce:

Blunt-force trauma.
Fractures.
Lacerations.
Contusions.
Abrasions.

During detonations, the body may sustain severe injury or amputation.

Small particles may also harm a victim when they are driven into unprotected skin.

Shrapnel Injuries

Shrapnel injuries are caused by solid fragments originating from the center of the blast.

Fragments may have serious effects when they penetrate the body, including:

Amputation.
Lacerations.
Blunt trauma.

Thermal Injuries from Explosions

Thermal injuries may result from the explosive flame front, which usually produces first- and second-degree burns.

Clothing may also be affected:

Synthetic fabrics may melt onto the victim.
Cotton fabrics may scorch.

Thermal burns are usually limited to first- and second-degree burns. Third-degree burns can also occur and may be fatal.

The brief exposure of the skin to the thermal event may cause damage to exposed surfaces, particularly those directly exposed to the source.

Seismic Injuries

Seismic effects from an explosion may collapse a structure or its structural elements.

Resulting injuries often include:

Blunt-force trauma.
Lacerations.
Fractures.
Amputation.
Contusions.
Abrasions.

Seismic effects from an explosion may collapse a structure or its structural elements.

Resulting injuries often include:

Blunt-force trauma.
Lacerations.
Fractures.
Amputation.
Contusions.
Abrasions.

Chapter Key Terms

Carboxyhemoglobin (COHb)

The carbon monoxide saturation in the blood.

Complex investigation

An investigation that generally includes multiple simultaneous investigations and involves a number of interested parties.

Entity in control

The interested party who has or represents ownership of the scene or is in effective management of the site, scene, or evidence, and is organizing, directing, or controlling the joint actions of the other interested parties.

Evidence custodian

Person who is responsible for managing all aspects of evidence control.

Hypoxia

Condition caused by a victim breathing in a reduced-oxygen environment.

Interested party

Any person, entity, or organization, including their representatives, with statutory obligations or whose legal rights or interests may be affected by the investigation of a specific incident. (NFPA 921)

Lividity

Pooling of the blood in the lower elevations of the body after death, which is caused by the effects of gravity.

Protocol

A description of the specific procedures and methods by which one or more tasks are to be accomplished. (NFPA 921)

Pugilistic attitude

A crouching stance with flexed arms, legs, and fingers.

Work plan

An outline of the tasks to be completed as part of the investigation, including the order or timeline for completion. (NFPA 921)