Remains of Palestinian leader Yasser Arafat are being exhumed to help determine the cause of his death.
Al Jazeera's Nadeem Baba reporting from the West Bank capital of Ramallah said that "according to Tawfiq al-Tirawi, the head of the Palestinian committee investigating Arafat's death, the process of exhumation started at midnight local time (22:00 GMT) on Monday".
"We're not getting this confirmed by other sources... this whole process has been surrounded by secrecy. What I can tell you is that some of my colleagues spotted members of the French team here in Ramallah to observe the exhumation and then be involved in those tests."
Three teams of international investigators traveled on Monday to the muqat'aa, the Palestinian Authority headquarters, where Arafat is buried. They could be seen bringing equipment to the site throughout the day.
A nine-month investigation, the results of which were broadcast earlier this year, found elevated levels of polonium on Arafat's final personal effects, raising new questions about what killed the longtime Palestinian leader.
French legal experts have also begun to gather evidence on the case in preparation for a possible trial, including testimony from people in the West Bank, according to Palestinian officials.
The teams are operating under a near-media blackout imposed by the Palestinian Authority, which had promised a transparent and open investigation. None of the investigators contacted over the past few days were willing to speak on the record.
And late on Monday, the PA said it would not allow lawyers representing Arafat's widow, Suha, to attend the exhumation, without offering any reason for its decision.
On Monday night, workers with hand tools drilled through more than four meters of concrete over Arafat's body. Investigators have collected several samples on the way down to took at polonium levels.
The whole process will take about ten hours, and Arafat will be reinterred in a military ceremony on Tuesday afternoon, according to al-Tirawi.
French, Swiss and Russian scientists
The French team includes three scientists - a toxicologist, a pathologist, and a generalist who works on legal medicine. The Swiss team, from the Institut de Radiophysique in Lausanne, conducted the forensic analysis in the initial investigation.
The Palestinian Authority also asked experts from Russia to conduct their own independent analysis. "One of them is from an organisation dealing with judicial medical experts, and the others are specialists connected to radiation," a source familiar with the Russian team said.
Only a handful of officials from the Palestinian Authority and Fatah were on hand for the exhumation. Arafat's family was not present, according to Palestinian officials.
It's unclear what condition Arafat's body will be in eight years after his death. Samples collected from bones and organs offer the best chance of finding evidence of polonium.
Al Jazeera's investigation studied the items Arafat had with him when he died: his comb, his toothbrush, even his iconic kaffiyeh, all of which were variously stained with his blood, sweat, saliva and urine. The items were provided by Arafat's widow, Suha.
His belongings were analysed by the Institut de Radiophysique in Lausanne, Switzerland, which discovered high levels of polonium-210. Further tests found that most of the polonium was "unsupported," which means that it did not come from natural sources.
But, even if it is present on Arafat's body, very little of the radioactive element will remain at this point. Polonium-210, the isotope found on Arafat's personal effects, has a half-life of 138 days, meaning that half of the substance will decay every four-and-a-half months. Scientists say that eight years is about the limit for recovering a useful sample, and a longer delay would have made it impossible to recover a workable sample.
'Certain people in certain positions'
It will take months for the scientists to finish analysing the samples they collect. Researchers will have to wait through at least one half-life to study the decay in their samples: Natural polonium replenishes itself after decaying, while unsupported polonium does not.
Once they finish their work, the French courts will determine how to proceed. Arafat died in a French military hospital, giving the French legal system jurisdiction over the case.
Suha Arafat asked a French court to open a murder investigation earlier this year, and the court granted that request in August. A team of French judges has already begun collecting Arafat's medical records and other evidence.
The group interviewed Arafat's widow, Suha, earlier this month. Tirawi also said that the investigators have gathered testimony in the West Bank from "certain people, in certain positions," but declined to offer any detail about their identities.
The French team has refused to speak to the press, and a team of Palestinian and French security agents prevented reporters from approaching them in their hotel. Even members of the Swiss team, which worked with Al Jazeera on the initial investigation earlier this year, were unwilling to comment on the exhumation, citing restrictions from the Palestinian Authority.
Palestinian security officers have tailed Al Jazeera reporters in cars and on foot, and at one point broke into the network's hotel rooms.
"They publicly praise Al Jazeera for the investigative breakthrough that breathed life into what was otherwise a very cold case, while at the same time they chase us around Ramallah to keep us from doing our jobs," said Al Jazeera's Clayton Swisher, who produced the investigation.