Poison killed Arafat. Former Hamas security chief arrested by Fatah

"An official Fatah investigation into the death of Fatah leader Yasser Arafat in 2004 has concluded that former Gaza security chief, Mohammad Dahlan, poisoned Arafat. Israel had long been blamed for the death of Arafat. Dahlan was also accused of corruption (stealing millions in foreign aid). Dahlan has long been held responsible for Hamas taking control of Gaza and evicting Fatah in 2007. This led to the Palestinian political split between Hamas and Fatah. Two months ago, Dahlan was finally forced out of Fatah, and arrested. The records captured in his home provide some of the evidence for the current accusations. While Palestinians like to blame all their problems on Israel, it’s become increasingly fashionable to admit that Palestinian officials tend to be corrupt and incompetent". Security Page August 13th

Dahlan

Haaretz adds: That Dahlan ordered Arafat's medicine bottle be burned is the only evidence offered and the story is being promoted because Dahlan was a rival to current President Abbas.
Arafat died of AIDS.  This is in the French medical record.
New York Times: Arafat died of a stroke and underlying conditions not determined, poisoning highly unlikely.