Which is the most likely indication of use of an ignitable liquid?

The selection of charring on the underside of a door as the most likely indication of the use of an ignitable liquid is based on the behavior of ignitable liquids in fire scenarios. When ignitable liquids are poured or used in a fire, they often create intense and localized hot spots. This can lead to significant charring in areas that are in direct contact with the liquid. The underside of a door, being relatively hidden from direct observation, can show distinct signs of charring where the ignitable liquid has contributed to the fire's intensity.

Charring occurs when the temperature is high enough to cause the wood or material to decompose, indicating not just exposure to heat but potentially to an accelerant. This evidence would be crucial in a fire investigation, as it suggests a deliberate act of ignition rather than a natural occurrence.

In contrast, while burnt blankets and rags, multiple points of origin, and a door propped open may provide insight into a fire's dynamics or behavior, they do not specifically indicate the use of ignitable liquids as clearly as charring on the underside of a door does. Burnt materials could suggest a range of different fire causes, and a door being propped open is more indicative of possible escape routes or ventilation rather