Fire Investigation INFOCUS podcast

S.3 Ep.17- Snow-Covered Scenes & Unusual Ignition Sequences: Thinking Outside the Box with Investigator Dennis Zigrang

Season 3 Episode 17

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In this episode, Scott Kuhlman and Chasity Owens sit down with Fire Investigator Dennis Zigrang of Fire Cause Analysis of Idaho for a wide-ranging conversation about the realities of fire investigation across different environments, career paths, and investigative challenges.

Dennis shares his journey from a 25-year career with the Long Beach Police Department into fire investigation, private-sector work, and eventually owning his own fire investigation company. He discusses the steep learning curve investigators face when transitioning from public to private fire investigation and why strong mentorship, documentation, scene methodology, and continuing education are essential throughout an investigator’s career.

The conversation takes investigators into an environment many rarely encounter: fire scene examinations in extreme cold and snow. Dennis explains how snow can affect scene processing, equipment and battery life, evidence recovery, transportation, hydration, and even the timing of a joint examination. From using leaf blowers to remove fresh snow to heating structures, packing specialized equipment for Alaska, and hauling evidence through deep snow, the episode offers practical lessons for conducting safe and effective cold-weather fire investigations.

The discussion also explores Dennis’s course “Unusual Ignition Sequences: Thinking Outside the Box and Outside the Origin,” including electrical failures, open neutrals, solar radiation, reflection and refraction, and self-heating fires. Dennis and the hosts examine why investigators must look beyond the obvious area of origin and understand the actual failure sequence that brought the heat source and fuel together.

Dennis also discusses the science and misconceptions surrounding self-heating and spontaneous ignition, including stained rags, oxidation, microbial activity, mulch, and potting soil, emphasizing the importance of research and scientifically supported conclusions.

Finally, the group explores how investigators are beginning to incorporate artificial intelligence and transcription technology into their workflows. Dennis shares how he uses Plaud, custom AI templates, voice dictation, and ChatGPT to organize interviews, build timelines, document scene observations, and streamline administrative portions of reports—while stressing that investigators still have to verify the information and remain responsible for the final work product.

From extreme-weather scene examinations and unusual ignition scenarios to AI, mentorship, documentation, and the differences between public and private fire investigation, this episode is packed with practical insight for both new and experienced fire investigators.

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