...poison? Aren't there actual recording(s) of the sounds? [1]

I guess this doesn't rule out them having bee poisoned on top of it, but it sure does raise eyebrows. Are they hypothesizing sounds were used to cover up the poison or something?

And given that even the article acknowledges some had concussions (here's another source I saw it in [2]) I'm not sure why the poison hypothesis is being entertained?

[1] https://www.youtube.com/watch?v=ghdLfQsztBo

[2] https://www.theguardian.com/world/2017/sep/14/mystery-of-son...