“Organic chemical tests were done on the bears’ stomach contents, liver, and kidneys to check for pesticides, euthanasia agents, and environmental pollutants. The results of these tests, as well as a test for ethylene glycol (found in antifreeze), were all negative,” the department posted on Facebook.
So, the presence of the yew leaves and seeds in the bears’ stomachs led to the conclusion that they died from plant toxin poisoning.