CFI Cheat Sheet 2026

The 30 highest-yield CFI facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. What mechanical condition can cause a dryer to start a fire even without electrical faults? → Lint accumulation in the exhaust duct restricting airflow and causing overheating
2. In the context of investigative methodology, what does 'negative corpus' mean and why is it problematic? → Concluding a fire was incendiary solely because no accidental cause was found
3. In fire investigation, what is the primary purpose of conducting interviews at the fire scene rather than an office? → To allow witnesses to reference visual cues that may trigger additional memories
4. At approximately what concentration level can well-trained accelerant detection canines detect ignitable liquid residues? → Parts per trillion (ppt)
5. What should an investigator do if they discover new evidence after the report has been filed? → Include it in a supplemental or amended report to ensure full disclosure.
6. An investigator is preparing to testify in a civil arson case and discovers their report contains a factual error. The investigator should: → Issue a corrected or supplemental report as soon as possible before testimony
7. Which NFPA standard provides the most comprehensive guidance on vehicle fire investigation? → NFPA 921
8. What is 'statement analysis' as applied in fire investigation interviews? → The systematic evaluation of written or verbal statements for linguistic cues of deception
9. Which agency has primary jurisdiction over a fire scene when a fatality is involved? → Law enforcement, with the fire investigator working in support
10. A fire investigator employed by a municipality is subpoenaed to testify in a civil case against their employer. The investigator's obligation is to: → Testify truthfully and completely regardless of employer interests
11. What is the PRIMARY purpose of continuing education requirements in Surveillance Methods & Technology for CFI professionals? → Maintaining current knowledge and competency as the field evolves
12. Why is maintaining a documented chain of custody for fire debris samples critically important? → It ensures evidence integrity and is required for admissibility in legal proceedings
13. A report written for an insurance company's subrogation attorney should be tailored by: → Maintaining complete factual accuracy while focusing on relevant technical findings
14. When planning the documentation phase of a fire investigation, what is the recommended sequence? → Photograph, sketch, then note-take
15. When interviewing a juvenile witness to a fire, what is the MOST important procedural consideration? → Ensuring a parent, guardian, or appropriate adult is present
16. When preserving DVR evidence at a fire scene, the chain of custody requires the investigator to: → Document the device serial number, date, time, and all persons handling it
17. In GC-MS fire debris analysis, what is the significance of identifying a 'target compound' in a sample? → It indicates the presence of a specific class of ignitable liquid within the sample
18. A CFI investigates a fire at a cryptocurrency mining facility. Which specific hazard unique to mining operations should be documented? → Overloaded electrical circuits from continuous high-draw GPUs
19. When documenting electrical evidence in a fire report, which finding would support an electrical cause hypothesis? → Beaded copper conductors found at the origin with primary melting characteristics
20. Which of the following best describes the purpose of a fire investigation report's 'scene examination' section? → To chronologically describe observations made at the fire scene
21. Under the 'fruit of the poisonous tree' doctrine, what happens to evidence discovered as a result of an illegal search at a fire scene? → It and any evidence derived from it may be excluded from court
22. A scene contains multiple areas with separate, distinct burn patterns that do not connect. This observation most supports which hypothesis? → Multiple points of origin, which may indicate incendiary fire
23. What is the purpose of including a 'blank' container in a fire debris laboratory analysis submission? → To confirm that the collection containers themselves are free of contamination
24. A fire investigator reviewing ATM camera footage notes the image is distorted near the edges. This is MOST likely caused by: → Wide-angle or fisheye lens barrel distortion
25. In planning an interview strategy for a major fire investigation, witnesses should ideally be interviewed in which order? → First responders first, then secondary witnesses, then subjects of interest
26. When documenting a fire scene involving suspected computer equipment, what is the correct sequence for digital evidence collection? → Photograph, document, preserve state, then collect
27. Which metadata element found in a surveillance video file is MOST critical for establishing the evidentiary timeline of a fire? → Timestamp synchronization and time zone data
28. Why is it important for fire investigators to have knowledge of relevant laws and regulations? → To avoid legal challenges to evidence and findings.
29. Which technique is used to verify whether a suspect's stated income is consistent with their actual lifestyle and assets? → A net worth analysis comparing known assets and expenses to reported income
30. A CFI suspects electrical involvement in a fire. Which methodological step should follow the initial hypothesis? → Identify and collect all potential electrical evidence for further analysis