Origin and cause reports are foundational documents in fire investigations. These reports serve not only to document the findings of the fire scene analysis but also become critical exhibits in legal proceedings, insurance disputes, and expert testimony. Given the intense scrutiny these documents often receive, their structure, content, and clarity must be beyond reproach. This blog post, based on expert training materials, outlines how to write a strong, methodologically sound, and legally defensible origin and cause report. We will cover essential sections, legal considerations, scientific methodology, and formatting guidelines, drawing on guidance from NFPA 921, NFPA 1033, and recent forensic science best practices.

Timelines are an important tool for developing, testing and/or eliminating hypotheses within a fire investigation. Timelines provide critical data for origin and cause determination, and one piece of timeline data can make or break these determinations. Consider, for example, how many times investigators must rule in or eliminate smoking/careless discard of smoking materials as a cause hypothesis. It is critical that fire investigators have access to a timeline analysis tool to help with their fire investigation.

The 1961 Bay of Pigs invasion of Cuba was one of President John F. Kennedy’s most controversial foreign policy calls, and is often cited as a case study in strategic miscalculation. Believe it or not, during the operation, a distinct failure to synchronize times had huge consequences and led to a failed attack.

In fire investigations, witness interviews are one of the most critical sources of contextual data. While the fire scene may offer burn patterns, material evidence, and electronic artifacts, it is often through witness statements that investigators learn when the fire was discovered, who was present, and what actions were taken before and during the incident. Yet interviewing is not just a task – it is a craft, especially when timeline construction is essential to origin and cause determinations.