The Jordanian doctor conducting the inquiry said on Thursday he was unable to diagnose Arafat based on his medical reports, but there were indications that he was poisoned by a toxic substance that was not detected at the time of his passing.

The death of former Palestinian leader Yasser Arafat was the result of an unknown poison.

That’s according to Abdullah al- Basheer, the Jordanian doctor leading the investigation.

Speaking at a news conference, Al-Basheer said the findings of the Lausanne-based Institute of Radiation Physics, which the Arab satellite channel Al-Jazeera used to test Arafat’s personal belongings couldn’t be conclusive due to the lack of previous examples of polonium poisoning.

Abdullah Al-Basheer, Arafat’s death inquiry commission, said, "We’re not one-hundred-percent sure to say Arafat died from polonium poisoning. It might be polonium, and it also can be other poisonous substances."

To confirm Al-Jazeera’s report, Arafat’s body needs to be exhumed for further tests.

The Palestinian leadership said it is ready to dig up his remains in order to aid the investigation.

It’s a decision that has been welcomed by the Palestinians.

But Palestinian investigators looking into Arafat’s death say they want to review reports from Switzerland’s Institute of Radiation Physics before deciding whether to exhume the leader’s remains.

The Palestinian leadership have invited the scientists from Switzerland to join the investigation, but they have yet to receive a reply.

Efforts to launch an international probe into the death of Arafat has come up against obstacles. The United States and France say any investigation into the death of Arafat could have negative consequences for the Middle East peace process.

Arafat died at a French hospital near Paris in 2004, three weeks after he was airlifted from his West Bank headquarters.