Fire Investigation

Fire Investigation Basics Work flow should start from minimally damaged areas progressing to ones with greater damage. Investigators should use typical forms of forensic documentation and collect evidence. Documentation can include notes and photographs Evidence collected typically is accelerant samples, fire items and other evidence that may not be directly fire related Fire Investigation Goal To try and determine… Point of Origin Heat source or sources Possible reason Point of Origin Where did the fire initially start? Burn patterns are used to help answer this question. The area of the most damage is commonly where the fire started Point of origin can be used to help determine the cause of the fire. Char Patterns Char patterns are created by very hot fires that burn very quickly that move fast along a path. This can result in sharp lines between burned and not burned material. Door char pattern can help determine which side of the door the fire was on. Floor char pattern can help determine if an accelerant was used and its path. V-Patterns Fire burns up, in a vertical V-shaped pattern, so a fire that starts at an outlet against a wall leaves a char pattern that points to the origin. Narrow V-shape: typically indicates a hot fire that could have had an accelerant. Wide V-shape: suggests a slow burning fire U-shape: indicates a "pool of origin" (not a point) such as a puddle of gasoline Heat Shadows Heat Shadows - Occur when an object shields another which can help determine the origin point. In a room a desk could shield the wall Glass Clues in Fire Investigation Light Bulbs (can aid in fire direction) Tend to melt toward the heat source Windows (can help determine how a fire burned) Presence of a dark soot layer on the glass could indicate a slow, smoldering fire Clear glass with an abnormal pattern of cracking could imply a very hot fire (*possibly due to an accelerant) Chimney Effect Chimney Effect- When the fire ignites at a point and the superheated gases rise upward and form a fireball This fireball will continue straight up to burn a hole in the ceiling (if present) which can help determine the origin of the fire. *Which would be directly underneath this area. Color of Smoke and Flames Smoke color- Indicates type of material burning Fire Patterns Image shows an ignitable liquid pour pattern Link to Lecture Slides: https://drive.google.com/file/d/1jvWUn3TCIQTbOG48z6TKImQFPQ71StlB/view?usp=sharing *Due to the description character limit the full work cited for "Fire Investigation" can be viewed at... https://drive.google.com/file/d/1Sl425BL7yfVKJhijtAy3SYev7tDaJ7v1/view?usp=sharing