I wonder which country did it?
The first forensic tests on samples taken from Yasser Arafat’s corpse have shown unexpectedly high levels of radioactive polonium-210, suggesting the Palestinian leader could have been poisoned with the rare and lethal substance.
The Swiss scientists who tested Arafat’s remains after the exhumation of his body in November 2012 discovered levels of polonium at least 18 times higher than usual in Arafat’s ribs, pelvis and in soil that absorbed his bodily fluids.

We will never know!
Lethal polonium dosing has a Russian signature and their labs tested negative. I wonder for whom they are covering?
Here is a list of the most probable suspects in his murder: 1) Israel……………….That we do know. But let’s explore what kind of real life crap happens when any leader is assassinated a bit further. Last week a U.S. drone assassinated the leader of the Pakistani Taliban just before he was going to enter into peace talks with the Pakistani government. So this week the Taliban selected one of the worst of the worst, Fazlullah, to take his place. Fazlullah was behind the attempted assassination of Malala. Now instead of a moderate in charge of the Taliban we have a radical militant in charge. Way to go you stupid neo-cons (Zionists). “The devil you know is always better than the devil you don’t know.”
Apparently you need a reactor to produce polonium in anything more than microscopic amounts, so that narrows it down somewhat.
Israel’s denial sounds transparently unconvincing.
As a nuclear power, would it have had easy access to polonium?