I already suspected that: when, in that fated day of 2004, the PA administration, led by the infamous Zionist agent Abu Abbas, brought a distraught Suha Arafat (his widow) to a separate room and somehow persuaded her not to demand an autopsy, it was extremely obvious.
The exact details were not known and the authorities and the media quickly buried the issue under a thick layer of political declarations and farce homages to the only person who had been able to rally the Palestinian People as one and who never fully renounced to their most important claims, becoming a thorn on the side of the colonial Zionist apartheid regime in Palestine (alias Israel).
Now, eight years too late, the case has been reopened. Suha Arafat accepted to give the late Yassir's personal possessions to a North American journalist working for Al Jazeera, Clayton Swisher. After some research it was discovered that they were all full of polonium 210, exactly the same radioactive poison that would kill Russian dissident Alexander Litvinenko in London two years later.
Why would Suha Arafat remain silent all this time and now open Pandora's Box? I have no idea but I'm sure that she has her reasons... personal gain reasons or lack of them thereof. She was in excellent terms with the former ruling clan in Tunisia, the Ben Ali family... until 2007, when she saw her citizenship revoked and her properties frozen. In 2011, after the Tunisian Revolution, she was brought to trial there for corruption.
Let's face it: Suha Arafat is no angel and never was... and her silence was surely bought with money and privileges. When these faltered she decided to do what she had not done in all this time: let the investigation on her husband's death go ahead and call for her husband's body be exhumed and an autopsy performed on it.
Better late than never.
In the research performed so far on his personal effects, very abnormal levels of polonium 210 have been found, specially where bodily fluids were present (up to 180 mBq, versus less than 7 mBq in a control sample), suggesting that the poisoning was done via food or water.
In addition, no obvious disease was found in Arafat in his late days by the doctors who attended him. Suspiciously enough the Laussane (Switzerland) hospital that hosted him in his last days had destroyed all samples taken from him, making more difficult (no doubt intentionally) the investigation of the death of the Palestinian leader.
While we await for further results, let me advance some guesses: this kind of poisoning by polonium 210 was used for decades by Soviet and then Russian spies. A large flow of Russian (or other ex-Soviet) Jews into the Zionist colonies in Palestine followed the collapse of the USSR in the 1990s, some of which, no doubt had and have connections with either the former KGB (now FSB) or the Russian Mafia (which some argue is impossible to pick apart from a Jewish mafia) or (quite often) both. So I'd bet that the origin of that plutonium is in Russia or some other ex-Soviet reactor (not necessarily: it can also come from Dimona or who knows?! )
However it was given to Arafat by the Zionist secret services, the Mossad, most likely with the support of some agents inside the Palestinian Authority, like maybe the infamous Abbas, on whom suspicions of being at the service of the Mossad have existed ever since.
See: Al Jazeera: What Killed Arafat? (hat tip to Jews sans frontieres), also Window into Palestine: Not a conspiracy theory anymore, which offers some interesting details.