Followers of the career of Yasser Arafat, who died in Paris almost eight years ago, will not be surprised that his ghost has now returned to haunt his successors at the head of the Palestinian Authority. Al Jazeera dropped a bombshell this week with an investigation into the still-unexplained causes of his death: a Swiss laboratory has found traces of polonium, the radioactive isotope used to assassinate the former KGB agent Alexander Litvinenko in London in 2006, on Arafat's toothbrush and clothing.

Palestinians have long believed that Arafat was poisoned by Israel, but the French hospital where he died found no traces of a poison, nor could it establish any other cause, such as infection, which caused him to suffer severe nausea and diarrhoea after he ate his supper on October 12, 2004.

No post mortem was conducted in Paris since his widow, Suha, did not request one, and no one thought at that time to look for polonium. Now she wants his body disinterred from its mausoleum in Ramallah, and the Palestinian Authority, which had never entertained such an idea before, apparently supports it. There is even talk of an international tribunal to reveal the truth about Arafat's death, on the lines of the body that is investigating the killing of Rafiq Hariri, the former Lebanese prime minister.

The Israelis deny killing Arafat, though clearly the issue was discussed among the leadership. Dov Weisglass, chief of staff to the then-prime minister Ariel Sharon, said this week that Sharon believed that killing Arafat would only inflame violence.

A conspiratorial mind would conclude that the Palestinian Authority, facing a potentially catastrophic political and financial crisis, is in dire need of a polonium hunt to distract its angry citizens. The Palestinian president, Mahmoud Abbas, has run out of road with his policy of security cooperation with Israel. The Israelis have become so comfortable that they have forgotten that the Palestinians even exist, and are certainly not thinking of allowing them a state.

Mr Abbas cannot pay June salaries to staff on the government payroll, thanks to diminishing handouts from foreign donors. In addition to the strain of living under Israeli occupation, the Palestinians have a new self-imposed burden: ballooning private debt that has translated into new BMWs and unsaleable real estate in Ramallah. Talk of a third intifada is on everyone's lips, one directed as much against Mr Abbas as at the Israeli prime minister, Benjamin Netanyahu.

But did the Israelis really kill Arafat? It is clear that his health took a knock in 1992 when he survived - miraculously as it seemed at the time - a plane crash in the Libyan Desert. His command of English seemed to get worse, and in later years all he could do was repeat the same old slogans. After the Israeli army destroyed most of his Ramallah headquarters and confined him to two rooms in the ruins, he became a tragic figure. But not one obviously at death's door.

Here is a description of Arafat's living conditions in October 2004 by the journalist Anton La Guardia: "Inside, the air is stale with the smell of sweat, food and a whiff of urine. Not surprisingly, Mr Arafat's doctors have advised the Palestinian leader to install air purifiers and an oxygen pump to make his bunker more bearable. He tries to get some exercise by walking in circles around his office … Mr Arafat's office doubles as cabinet room and dining mess."

The Israeli army could have killed him at any time. At one stage they were right outside the door of his office, though they would have had to contend with his trusty Czech-made machine pistol. Mossad, like the KGB, has more sophisticated ways of killing than blowing down the door. In 1997, they tried to kill Khaled Meshaal, the Hamas leader, in Amman by injecting him with poison. The assailants were caught by Mr Meshaal's bodyguards, and Israel was forced to deliver the antidote.

Polonium had not been thought of as a murder weapon until it was discovered, after exhaustive other tests, as the poison that killed Litvinenko. It left a radioactive trail all the way from Moscow airport to the London hotel where the ex-spy drank the fatal cup of tea, so it is unlikely to be used again. But back in 2004, polonium was still a secret weapon. It is rarely found in nature, but is produced by nuclear reactors, so Israel would have a supply.

But who would have had the chance to administer poison to Arafat? Access to Arafat was tightly controlled, and he was a cautious, even picky, eater. Since the Al Jazeera documentary was aired, no one seems to have recalled the conspiracy theory that was doing the rounds at the time of his death - that some members of the Arafat circle wanted him out of the way so they could make a new start after the catastrophe of the second Intifada.

As Arafat lay dying, his wife Suha rang Al Jazeera to warn the Palestinians live on air that a bunch of conspirators who wanted to bury "Abu Ammar alive" were on their way to Paris. As anyone could see on their TV screens, the delegation arriving in the French capital from Ramallah included Mr Abbas and the current leadership.

Suha's comments can be dismissed as the anguished cry of a wife faced with the realisation that the political caravan has left her husband behind, even while his heart still beats. But the suspicion has remained: if Arafat was poisoned in his two-room Bastille, then someone in his entourage must have put the poison in his food or drink, or at least been in on the plot. And if it was polonium, a foreign nuclear power - presumably Israel - must have supplied it. It is hard to think of a more deadly political combination for Arafat's heirs.

The polonium theory is far from confirmed, and may never be. Arafat did not lose his hair, a clear sign of radiation poisoning. One thing is certain. If polonium is confirmed by recognised experts as the cause of death, then the blame trail will not stop at Israel. The Oslo "peace process", which has been moribund for years and still exists in a virtual diplomatic world for lack of anything else, will be well and truly dead.