The Belleville Fire Investigation Unit (FIU), is charged with determining the origin and cause of each fire that occurs within the corporate city limits of Belleville. The FIU unit members are certified as fire investigators through the State of Illinois. Two of the supervising members are also nationally certified as investigators through the International Association of Arson Investigators (IAAI). The members are extensively trained in fire pattern recognition, photographing, diagramming, evidence collection and report writing. Each member may participate in courtroom testimony and depositions rendering expert opinions.
Fire investigators use the guidelines set forth in NFPA 921 classifying each incident in one of four categories.
• Incendiary - Fires that are intentionally and maliciously set.
• Accidental - Fires caused by non malicious electrical, mechanical, chemical, and other careless means.
• Undetermined - Fires that have more than one possible ignition source and where one specific cause cannot be determined.
• Natural - Fires ignited by acts of nature, such as lightning.
All fires classified as "Incendiary" are forwarded to the Belleville Police Department for further investigation. The FIU has a close working relationship with the Belleville Police Department and the arson detectives assigned to each case. Investigators may, on some occasion, work in conjunction with the Office of the State Fire Marshal (OSFM) and Federal Bureau of Alcohol Tobacco and Firearms (FBATF).