At a fire scene, what characteristics should an investigator look for to identify the fire's point of origin? What circumstances may affect these characteristics?

Question

What will be an ideal response?

Answer 1

Answer should include points such as the following:
Normally a fire tends to move upward, and thus the origin is most likely to be located closest to the lowest point that shows the most intense characteristics of burning. Sometimes, as the fire burns upward, a V-shaped pattern forms against a vertical wall. Because flammable liquids always flow to the lowest point, more severe burning found on the floor than on the ceiling may indicate the presence of an accelerant. If a flammable liquid was used, charring is expected to be more intense on the bottom of furniture, shelves, and other items than on the top.
However, many factors can contribute to the deviation of a fire from normal behavior. Prevailing drafts and winds; secondary fires due to collapsed floors and roofs; the physical arrangement of the burning structure; the presence stairways and elevator shafts; holes in the floor, wall, or roof; and the effects of the firefighter in suppressing the fire—these are all factors that the fire investigator must consider before determining conclusive findings.