Techniques used in arson case now seen as outdated
I find this interesting, especially since seventeen years later — and five years after Willingham was executed in connection with the case — nine fire experts have raised the possibility that the blaze may have indeed been accidental, citing revised standards in arson investigations.
The arson investigation into the Willingham case was conducted before the 1992 publication of what has since become the standard for arson science: NFPA 921, a Guide to Fire and Explosion Investigation, published by the National Fire Protection Association. Vasquez and Douglas Fogg, then assistant fire chief for Corsicana, cited more than 20 indicators to conclude that the fire was intentionally set. But several of those indicators have since come under question in light of the newer standards in NFPA 921.
1. "Crazed glass," a weblike pattern earlier assumed to be caused by use of a liquid accelerant. Now it is also attributed to the rapid chilling of hot glass by water from fire hoses.
2. "Pour patterns," "trailers" and "puddles," markings suggesting that someone dumped accelerant. A "post-flashover fire" — which spread from single objects to engulf an entire room, reaching temperatures of more than 2,000 degrees — can also produce floor burn patterns that cannot be distinguished from those caused by liquid accelerants.
3. Multiple points of origin, which can indicate that a fire was deliberately ignited. But other causes, such as embers or drop-down burning, can produce the same effect, experts said.
full story and photos here;