Here is a long-standing federal agency, Alcohol, Tobacco and Firearms, basking in their scientifically outdated historical about arson caused fires. They use a “process of elimination” theory of criminal actions. Others call it old fashioned and biased.
One must realize that ATF provides training modules for international. state and local law enforcement and prosecutors. All of this is reminiscent of the FBI’s hair matching bunch disseminated their scientifically rejected methods for decades. Here’s some links.