Authorities believe it's either ricin or tetrodotoxin, the killer ingredient in puffer fish.
We should keep an eye on this...also watch the video.....a well planned military operation.
I doubt it was ricin because of the quick action. Some years ago I read an article about ricin, and was impressed by the efficiency of the poison and its method of action. Each active molecule of ricin attaches to a ribosome in the mitochondria of one cell, permanently knocking out its energy metabolism. It takes some hours for that to take effect, and Mr. Kim was affected in minutes.
I don't know anything about the mechanism of tetrodotoxin, but as you say, it is the puffer fish toxin. It seems, well, Asian, which is suitable here.