What is a fire pattern that could be indicative of arson?

Hourglass-shaped patterns can indicate arson because they suggest the use of an accelerant. Such patterns typically form when a fire is intentionally set with a substance that accelerates the flames, causing them to burn in a distinct shape that is not typical of accidental fires. These patterns often result from igniting materials in a way that creates a rapidly spreading fire, which can take on the hourglass shape as the flames consume available fuel.

In contrast, randomly scattered burn marks do not suggest a deliberate arrangement, and uniform or symmetrical patterns could imply a more controlled burn that might occur unintentionally. These other burn characteristics do not carry the same implications of intentional manipulation or strategic ignition that an hourglass shape typically does. Thus, recognizing distinct patterns like the hourglass is crucial for investigators in identifying potential cases of arson.