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FIR 4315, Fire Investigation Technician 1

Course Learning Outcomes for Unit V

Upon completion of this unit, students should be able to:

8. Examine the procedures for fire scene documentation.
8.1 Describe the various methods of documenting the fire scene.


Learning Outcomes
Learning Activity


Unit Lesson
Chapter 14, pp. 252–257
Chapter 15, pp. 270–284
Chapter 16, pp. 286–302
Unit V Case Study

Required Unit Resources

Chapter 14: Documentation of the Investigation, pp. 252–257

Chapter 15: Physical Evidence, pp. 270–284

Chapter 16: Origin Determination, pp. 286–302

Unit Lesson


When performing your duties as a fire investigator at the scene of a fire, all forms of documentation should be
used to make sure that the scene and what has happened at the scene is recorded. This should involve
photographs with a photo log, diagrams, field sketches and notes, as well as the final report. This all needs to
be done so that the scene can be put back together based on the information that the investigator has
documented. The idea behind all of this documentation is to be able to paint a picture of the scene for those
who could not be at the scene—prosecutor, judge, and jury, for example.

There is also the need to take care of the physical evidence from the fire, documenting and preserving each
item that is collected. This includes storing the evidence in a manner that is consistent with the rules of
evidence. The evidence may need to be taken to the crime lab for proper analysis and determination of what
was found. The final part of this unit will look at the process of origin determination. This is the review of the
scientific method and how the fire investigator needs to make sure that a constant methodology is used in
every investigation.

Utilizing a systematic and consistent approach with each investigation is paramount for maintaining a case
that can stand up in court. This includes the selection of final hypotheses and making sure that the approach
was proper to reach a conclusion of what occurred. Chapters 14, 15, and 16 in your textbook cover these
three sections of the course: documentation of the investigation, physical evidence, and origin determination.
This lesson introduces each of these sections.

Documentation of the Investigation

The fire investigator must understand the various techniques available for documentation of the fire scene.
This would include any documentation: written, electronic, or photographic. Written documentation consists of

Fire Scene Documentation

FIR 4315, Fire Investigation Technician 2


field notes that are written down while inspecting the scene and the hand sketches that are drawn to show
where things are found at the scene. The investigator can also note on the sketch and field notes where he or
she was standing when each photo was taken. This allows the investigator to return to the office and then
complete the actual investigation report. Electronic documentation usually refers to the computer-based fire
report that is produced at the end of the investigation, but there are also apps that can be used to take field
notes and do field sketches of the scene. This gives you different views of the same fire scene, allowing for
the information to be assembled in the minds of people involved in the case who do not get to see the scene
of the incident. Each aspect of documentation requires a commitment by the investigator to make sure that
the story of the scene is being told.

The first form of documentation that can be easily accomplished, due to the popularity of digital cameras, is
photography. Documentation by photography will allow an actual picture of the scene to be shared with
anyone involved in the case. The photos that are taken on the scene must be able to be authenticated in
court as a true representation of the scene. If the photo is adjusted or edited on the computer, then the
original photo has to also be presented to show what was actually seen when photographing the scene. This
can include taking wide views of the scene and then taking several close-ups so that they can be put together
to show the scene in both views. As the photos are being taken, the investigator should be logging each
photo in a photo log and diagraming where each photo was taken in relation to the scene (International
Association of Fire Chiefs [IAFC], International Association of Arson Investigators [IAAI], & National Fire
Protection Association [NFPA], 2019). The photos should be taken of the entire scene and include the exterior
of the house and any bystanders (that might include an arsonist if the fire was arson). If the investigator
arrives on the scene before suppression efforts are completed, photos of the suppression activities should be
included to help explain how it impacted the investigation. Of course, the interior pictures will be the most
important aspect of the entire scene; this is where the fire patterns and findings that help determine the point
of origin will come into play. The best part about utilizing digital photographs is the fact that there is no extra
cost for taking additional pictures.

Photos alone are not the best way to show the scene to people who were not able to see it in real time. The
investigator needs to also be able to provide a clear diagram and any field sketches that were taken when
describing the case. The field sketch is drawn as the investigator walks through the scene. Each item is
placed on the sketch, and once the investigation is complete, the sketch is turned into a formal diagram. The
sketch and diagram should show where all items in the structure were when the investigator conducted the
analysis of the building. The sketch and final diagram will need to show any fire patterns that are found and
any items that were collected for evidence. The idea behind the diagram and photos is to help court jurors
understand the layout of the fire scene, which will help when describing what happened. These items will be
combined with the written report to form the file of documents known as the final investigation report.

Physical Evidence

The biggest challenge for a firefighter who becomes a fire investigator is understanding the rules of evidence.
If you are required to collect your own evidence, then you will need to understand what evidence is and how
to process that evidence. The investigator needs to understand the fire scene and the evidence that will most
likely be found as well as how to document the fire patterns and debris of the fire.

The focus for the fire investigator is to train the firefighters prior to the incident in how to not destroy or taint
evidence. The other issue is avoiding the contamination of the evidence while collecting the items. The fire
investigator needs to work with law enforcement and the crime lab on strong policy and training on how to
collect evidence or have the evidence specialist from the police department collect the evidence. The most
important part of the evidence collection is to make sure that there is documentation in the diagram and the
report of where this evidence was found as well as pictures of the evidence before and during collection. The
final item is how the evidence is transported and stored or taken to the lab for analysis, if that is needed. This
should also be covered in the policy that is developed by the investigator. The collection, documentation,
examination, and storage of the physical evidence is the responsibility of the lead investigator in each case.
Without proper evidence collection, the evidence could be classified as spoliation, resulting in dismissal from
the court systems (IAFC et al., 2019).

FIR 4315, Fire Investigation Technician 3


Origin Determination

Now that the discussion has come to the point of origin of the fire, it needs to be narrowed down to the area in
the structure where the fire originated or where ignition occurred. The investigator must determine where the
ignition source and first fuel burned came together in this particular fire. Consistency in the inspection of the
structure is the most important part of the analysis that the investigator is conducting.

Each time the fire investigator conducts an investigation, he or she needs to follow a systematic approach to
working through the structure. The utilization of the scientific method will help to keep the investigator’s work
on track and focused on the goal at hand. The investigator needs to find not only the point of origin but also
how the fire spread through the structure. This will require developing a hypothesis of how the fire was
spread, a reconstruction of the fire scene, and an overall initial hypothesis of the fire. The scientific method of
origin determination is outlined perfectly in Figure 16-1 on page 287 of your textbook.

One of the difficulties with putting the scene back together is knowing where things were prior to the fire and
how they ended up where they did. The best resource for figuring out where these items were is by asking the
occupants or possibly a neighbor who may have known. Once this is figured out, the understanding of what
caused the fire to spread and how it spread can be researched to further the investigation.

Analysis of the data would be the next step in the systematic process. This can be accomplished by looking at
fire patterns and following the spread of the fire. The heat of the fire in a particular area based on the type of
fuel and how long it burned in that area can be important. The depth of char is not as important as it was once
considered, but it can tell a part of the story, especially if it is supported by other indicators that are found
showing that the fire burned longer in that area. The investigator can use an origin matrix analysis, like the
one in Figure 16-6 on page 297, to help determine factors that impact finding the origin. The next step is
testing the hypotheses that have been developed in relation to the fire that is under investigation. This testing
process involves looking for credible data that will align with the data that was gathered from the analysis that
was conducted during the investigation.


Finding the point of origin in a fire may seem daunting for a new investigator, but through the use of a
systematic approach to each investigation and following the scientific method, the process will not only come
together but be worth the time and effort that has been put into the investigation. The investigator should be
able to help the people involved in the court case understand the scene and what was found on the scene.
This is best done through photos, diagrams, and descriptions in the final report. One of the requirements of
fire investigations that firefighters may not be prepared for is that of collecting physical evidence; work with
law enforcement to determine the best way to accomplish this task in your investigations.


International Association of Fire Chiefs, International Association of Arson Investigators, & National Fire

Protection Association. (2019). Fire investigator: Principles and practice to NFPA 921 and 1033 (5th
ed.). Jones & Bartlett.

Suggested Unit Resources

In order to access the following resources, click the links below.

This article explores what happens when a sprinkler system in an office building does not function correctly.

Lai, C.-M., Ho, M.-C., Chen, C.-J., Tasi, M.-J., & Lin, T.-H. (2010). Experimental investigation of an office fire

with a partially impaired sprinkler system. Fire Technology, 46(3), 611–627.

FIR 4315, Fire Investigation Technician 4


This article covers the author’s experience looking at various commercial cooking fires and what conclusions
were reached.

Horton, D. (2015). Lessons learned from commercial kitchen fire investigations. ASHRAE Journal, 57(2), 18–


This article looks at the need to understand that the entire investigation must be considered before reaching a

Lentini, J. (2012). Arson or accident? Chemistry & Industry, 76(12), 34–41.

This article discusses the issues that arise with the investigation of fires by insurance companies and the
results of the investigation.

Pavlisim, M. J., Williams, H. E., & Seidler, J. A. (2005). Insurance related fire investigation issues. FDCC

Quarterly, 55(4), 407–433.

This article discusses the impact that an accelerant will have on wood chips burning.

Zong, R., Liu, X., Li, F., & Ye, J. (2016). Influence of fire accelerant on the thermal degradation and ignition of

wood chip. Australian Journal of Forensic Sciences, 48(5), 538–548.

Learning Activities (Nongraded)

Nongraded Learning Activities are provided to aid students in their course of study. You do not have to submit
them. If you have questions, contact your instructor for further guidance and information.

This is an opportunity for you to express your thoughts about the material you are studying by writing about it.
Conceptual thinking is a great way to study because it gives you a chance to process what you have learned
and increases your ability to remember it.

Before completing your graded work, consider completing the “Case Study” and “On Scene” exercises for
Chapters 14, 15, and 16. Completing these exercises will help you with your graded work.

The exercises can be found on the following page numbers:

Chapter 14: “Case Study,” p. 252
Chapter 14: “On Scene,” pp. 267-268
Chapter 15: “Case Study,” p. 270
Chapter 15: “On Scene,” p. 284
Chapter 16: “Case Study,” p. 286
Chapter 16: “On Scene,” pp. 301-302

If you have any questions or do not understand a concept, contact your professor for clarification.

  • Course Learning Outcomes for Unit V
  • Unit Lesson
    • Introduction
    • Documentation of the Investigation
    • Physical Evidence
    • Origin Determination
    • Conclusion
    • Reference
  • Learning Activities (Nongraded)

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