Warfarin. Rat Poison.
A worrying twist..
yep. Chemically it belongs to coumarin family. That much I still remembered, but the word 'warfarin" somehow eluded me at the time. Hopefully, it's only the lousy memory and not an alzheimer onset.
If you put enough of that stuff in food to poison that many people, wouldn't the taste be noticeable? I think it must be some kind of exotic poison that is lethal in small doses that nobody would notice.
warfarin would do this, but takes a day to work, not hours. It stops the liver from making proteins to clot blood, but the proteins already there stick around for about a day.