http://www.aljazeera.com/programmes/whatkilledarafat/2012/07/20127383653774794.html
Eight years after he died, no one knows what killed former Palestinian leader Yasser Arafat. Tests have revealed that Arafat’s personal belongings(his clothes, toothbrush, and trademark kaffiyeh) contained abnormal levels of polonium, a rare, highly radioactive element.
Polonium is the same element that killed Alexander Litvinenko, the Russian spy-turned-dissident who died in London in 2006 (and was found to have been poisoned after polonium slipped into his tea at a sushi restaurant).
May his soul rest in peace. Ameen