and how did AA know that info at 11PM the night it happened?
My opinion is this sounds like the game of telephone we played as kidlets.
Sometimes all it takes is for someone to make a random statement and it gets repeated. It could have been something as simple as overhearing something and misunderstanding it or not knowing the full content surrounding the statement.
EMT says to partner/police/hospital radio (and is overheard by Person A): "her breath smells like lighter fluid, nail polish remover, helium" - to me, I don't know how they could distinguish her breath odor from surrounding fire odors, but presumably professionals who've experienced it would know.
Person A hears it correctly and repeats it as fact when it's just someone's conjecture.
Person A could have misheard something and repeated it as fact.
Person A could have heard correctly and put their own interpretation to it and repeated it as fact.
Person A could be thinking something, then overhear something they thinks confirms their own theory and repeats it as fact.
Person A may something that nobody else knew and thought they'd be safe in repeating it as though they heard it at the scene.
Person B could have misheard and repeated it as fact. Many opportunities for mistakes.