I’ve been trying to find out more about this because the story doesn’t make any sense:
“he approached the sleeping woman, and then lit her on fire with what was believed to be a lighter. She added the victim’s clothes became fully engulfed in a matter of seconds.”
Clothing shouldn’t just be flammable like that without some kind of accelerant.
https://www.cpsc.gov/Regulations-Laws--Standards/Statutes/Flammable-Fabrics-Act
Yes, wool is definitely a flame retardant. I seem to remember that while cotton fibres will burn up, woven cotton textiles will burn only poorly and slowly. That is, they are flame retardant, but not flame resistant. Most synthetic clothes will first melt, and if it’s hot enough that the melt burns, they’ll burn quite well.
I saw comments about tight woven cotton being flame resistant. It sounds like it helps deprive oxygen from the flame. Any frays and stray thready bits lose that protection.
Textiles are surprisingly interesting!