French prosecutors have opened an investigation into Yasser Arafat's death, eight years after coroners ruled that the longtime Palestinian leader and Nobel Peace Prize laureate had succumbed to a stroke. Arafat's family was never convinced that he had died of natural causes, and, citing new evidence uncovered in an al-Jazeera TV documentary, Arafat's widow, Suha, and his daughter Zawra filed a murder complaint this summer. Is there really a chance that Arafat was murdered? Here's what you should know:

What was the official cause of Arafat's death?
Arafat, who was 75, was air-lifted to a French military hospital from his Ramallah headquarters after he fell violently ill in 2004. He died two weeks later. According to medical records, Arafat succumbed to a massive stroke resulting from a bleeding disorder that was caused by an unknown infection.

How does his family think he died?
They believe that he might have been poisoned. The suspicions stem from evidence presented in an al-Jazeera TV documentary broadcast in July. The documentary team commissioned Swiss scientists to analyze Arafat's belongings, and they found "significant" traces of polonium-210, a rare and highly toxic radioactive element, in his clothes, including his trademark keffiyeh, and his toothbrush.

Are assassins known to use this poison?
It wouldn't be unprecedented. Polonium was used in 2006 to kill Alexander Litvinenko, a Russian-spy-turned-Kremlin critic who died in London after drinking tea laced with polonium. The highly lethal substance is rare outside military and research labs, so Palestinians say the substance's alleged presence on Arafat's clothes is consistent with their theory that Arafat was killed by Israeli spies. Still, the Swiss scientists hired by al-Jazeera say their results weren't conclusive, and that Arafat's remains will have to be exhumed to clear up the matter. The Palestinian Authority only added to the confusion by first approving the exhumation, then saying it would have to study the matter further.

How likely is it that Arafat really was murdered?
Not very, according to medical experts who have reviewed Arafat's records. They say the evidence of Arafat's stroke are not consistent with poisoning of any kind. Still, the inquiry was welcomed by Palestinian and Israeli authorities alike. Senior Palestinian official Saeb Erakat thanked France for trying to shed light on the circumstances of Arafat's "martyrdom." Israeli foreign ministry spokesman Yigal Palmor said his government hopes the investigation will, once and for all, squelch the "hare-brained allegations made against us."

Sources: BBC News, Christian Science Monitor, Expatica, Telegraph