Perhaps this is all a hoax aimed at getting him a new identity and REALLY going into hiding.
If CNN said it...I don’t believe it.
Well, I mean, if you're force-fed poison, naturally you die.
The first I read was that the assailant splashed a liquid in his face.
Compressed air delivery
Micro-powdered Ricin (castor bean) inhaled from the cloth put over his face. Grabbing and restraining caused him to inhale deeply. Net result— bronchial contraction and death. Probable. Not cyanide (prussic acid) as this leaves odor of ‘burnt almonds’ and is diagnostic as is the skin discoloring.
A guess.