http://www.aljazeera.com/programmes/whatkilledarafat/2012/07/20127383653774794.html?utm_content=automate&utm_campaign=Trial6&utm_source=NewSocialFlow&utm_term=plustweets&utm_medium=MasterAccountAl Jazeera argues that Arafat's corpse and personal effects contained 9x the usual amount of Polonium-210 as usually found in humans. Polonium is, of course, the radioactive poison used to kill Alexander Litvinenko.
Arafat died in 2004. He showed many of the same symptoms in his last days as Litvinenko did.