It was the element Polonium :) does that help?
POLONIUM-210
We don't know at this moment in time, as there are many suspects
A post-mortem examination suggested Mr Litvinenko had died after being poisoned with the radioactive substance polonium-210.
Martin Keamy (the mercenary)
yes
It doesn't, monarch butterflies are poisonous and predators tend to stay away from poisonous things.
Suicide from the bite of an asp, a poisonous snake.
because it killed loads
She is said to have killed herself with a poisonous snake, but it was most likely poison.
She ate a bunch of poisonous berries D:
Alexander Litvinenko , a former FSB agent who fled Russia to avoid court trial and was given asylum in Great Britain, was killed by poison. The official cause of death was acute radiation poisoning. He supported the exiled Boris Berezovsky and accused Russia of bombings and terrorism to bring Vladimir Putin into power.
Nightlock. They pop up many times in later books.