Lucretia just infodumped Aya Brea?!
The term "spontaneous human combustion" refers to cases in which a human body is found with significant portions of the torso reduced to ashes, while the head and extremities show much less damage and the immediate surroundings of the body are only minimally affected. Typically, no observable source of ignition is found near the victim, and a foul-smelling, oily residue is noted.
In the past, such cases were erroneously attributed to supernatural causes, as the phenomenon tends to occur in the absence of any witneass.
A specific sequence of events is required for a human body to be reduced to ashes. The victim must first die from the initial flame, allowing the body fat to begin melting. A tear in the skin then has to occur so that the melted fat can soak into the charred clothing, igniting a wick effect that produces localized heat over an extended period. For this reason, the modern explanation favored today is the "fat wick burning" hypothesis rather than spontaneous combustion.