Running an Arson Investigation Review Worksheet
The review worksheet is a checklist that investigators use to verify every step of an arson determination before closing a case. I have filled out dozens of these across fire scenes that ranged from simple electrical faults to intentional accelerant fires. The form itself is straightforward, but the answers you write on it are what hold up in court or insurance hearings. Most departments use a modified version of the NFPA 921 worksheet combined with their own state requirements. You are not grading yourself. You are building a defensible record that shows you considered every reasonable hypothesis and eliminated it based on evidence.
Arson Investigation Review Worksheet Answers
When you sit down to complete the answers section, start with the basics before moving to interpretations. The first block covers scene documentation. You need to record the date, time, location, weather conditions at the time of fire, and access points. I once missed noting that a back door had been propped open with a brick, and the defense attorney used that gap to suggest unauthorized entry. Write it all down. The next section is origin and cause. This is where most investigators make mistakes. You must identify the area of origin using triangle method, point of origin analysis, and burn pattern interpretation. Do not guess. If you cannot determine the exact point of origin within reasonable scientific certainty, state that clearly in the answer field rather than forcing a conclusion. Here is a practical edge-case I ran into last year. A mobile home fire showed clear V-patterns pointing to a space heater, but the accelerant test strips came back negative. I initially wrote electrically-induced fire as the answer. Then I noticed the heater plug was melted at the cord connection, not the outlet. The cord had been frayed and resting on a metal surface. I revised the answer to accidental electrical fault after documenting the chain of failure. That detail saved the case from being thrown out on appeal.
The evidence collection block requires you to note what samples were taken, where from, and who collected them. Accelerant samples go in vapor-tight containers. Physical evidence like melted wiring gets bagged separately. I have seen cases fail because the investigator put a soil sample in the same container as an accelerant swab. Cross-contamination ruins everything. Witness statements belong in the next section. Record who spoke to, what they said, and whether their account is consistent with physical evidence. If a witness claims they saw someone leave the building moments before the fire, but the fire alarm log shows no prior activation, note the discrepancy. Do not ignore it. The final answers cover classification. Arson, accidental, undetermined, or suspicious. This is not a suggestion box. The answer must reflect what the evidence supports. If you cannot rule out accidental causes, write undetermined. Courts respect honest uncertainty more than forced conclusions.
Get the Full Details
One thing beginners miss: the worksheet answers should reference specific exhibit numbers, photo IDs, and lab report citations. Writing "accelerant detected" without linking it to Lab Report #4 and Exhibit C is not an answer. It is a claim. Attach the references. Another counter-intuitive point: reviewing your own answers after 24 hours often reveals gaps you missed. I usually draft the initial answers, then come back fresh the next day. The second pass catches inconsistencies like a burn pattern description that contradicts the wind direction note. The worksheet also has limitations. It assumes you have enough time at the scene. In active call departments, that is often not the case. If you cannot complete the worksheet fully, note the constraints in the answers and schedule a follow-up. Do not submit an incomplete form as final.
For download and templates, most states provide blank worksheets through their fire marshal offices. The NFPA 921 appendix includes a sample format. Use your department's approved version. Do not invent your own unless authorized. I have also seen investigators skip the elimination of reasonable hypotheses section. This is a critical answer block. You must show you considered and rejected alternative causes. If a space heater was present but the thermostat was intact and the cord showed no arcing marks, document why you ruled it out. The answer field is not for conclusions alone. It is for reasoning. Speed matters here. A complete worksheet with thorough answers usually takes 45 minutes to an hour for a standard residential fire. Complex commercial cases can take several hours. Budget accordingly. Rushing produces errors that survive only until cross-examination.
Training helps. I recommend completing the IFSTA arson investigation module before relying on the worksheet alone. The difference between a technician who fills out the form and an investigator who uses it as a thinking tool is significant. The worksheet is not a checkbox exercise. It is a structured reasoning framework. If you need current templates, check your state fire marshal website or the NFPA store. Some departments require digital submission through evidence management systems. The format varies. The content requirements remain the same: document, analyze, conclude, reference. One final note on answer quality. Write in past tense. Use active voice where possible. Avoid qualifiers like "possibly" or "might have been" unless the evidence truly supports uncertainty. When you say "the fire originated at," you are making a factual statement backed by observation. Treat it with that weight.
The worksheet answers are permanent. They become part of the case file, discoverable by defense, and potentially read aloud in trial. Draft them as if a jury will see every word. That mindset changes how you approach each section. Common pitfalls include incomplete photo documentation references, missing chain-of-custody entries, and conclusions that exceed the evidence. I once saw a worksheet answer write "deliberately set" based solely on multiple ignition points. The lab had not confirmed accelerant presence. The answer was stricken on motion. The investigator should have written "suspicious circumstances noted, cause undetermined pending lab results." Practice with mock scenarios helps. Run through hypothetical fires with a colleague and compare worksheet answers. You will spot gaps in reasoning that you missed when working alone. I do this quarterly with my team. The exercise rarely fails to reveal at least one questionable answer.
The review process itself matters. Before signing off, walk through each answer block systematically. Check that every claim has supporting evidence cited. Verify that all exhibits are accounted for. Ensure the conclusion matches the weight of the findings. If anything feels weak, strengthen it or downgrade the conclusion. Good worksheet answers are boring. They are factual, referenced, and logically sequenced. They do not need flair. They need defensibility. That is the entire point.
