Al Jazeera sources said Yasser Arafat's remains have been reburied, just hours after being exhumed as part of a probe into his death.
The same sources said the forensic pathologists were "not able to fully remove the body from the tomb," so they took samples from portions of it.
Because Arafat's remains were not fully removed, Palestinian authorities could not do a proper military funeral as was expected.
The Palestinian Authority will hold a press conference on Tuesday afternoon to discuss the exhumation.
Arafat died of a stroke in 2004, but the underlying causes of death remain a mystery.
Earlier, sources told Al Jazeera that Palestinian doctors collected samples with the help of an international teams from France, Russia and Switzerland.
Three doctors, three forensic scientists, the health minister, the justice minister, and heads of the lawyers and doctors syndicates were reportedly present during the exhumation.
Al Jazeera's Clayton Swisher also reported that the Palestinian attorney general, with the help of French prosecutors, had started interviewing dozens of Palestinian officials close to Arafat about the conditions the leader was living under before his death in 2004.
Three teams of international investigators travelled on Monday to the muqataa, the Palestinian Authority (PA) headquarters, where Arafat is buried.
Al Jazeera investigation
A nine-month investigation by Al Jazeera found elevated levels of the substance in Arafat’s final personal effects.
The findings, which were broadcast in July, suggest that there was also a high level of polonium in Arafat’s body when he died, raising fresh questions about what killed the longtime Palestinian leader.
The cause of Arafat’s death has long remained a mystery.
Some reports speculated that he died from AIDS, cirrhosis of the liver, or other diseases, but medical experts who studied his final medical records told Al Jazeera that he was in good health until he suddenly fell ill in October of 2004.
Many Palestinians have long believed that Arafat was poisoned by Israel, a charge Tirawi repeated on Saturday.
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 PA, which had promised a transparent and open investigation.
None of the investigators contacted over the past few days was 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 metres of concrete over Arafat’s body. Investigators also collected several samples on the way down to look at polonium levels.
The whole process was to take about 10 hours.
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 PA 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.
|Complete coverage of Al Jazeera's special investigation
Only a handful of officials from the PA and Fatah were on hand for the exhumation. Arafat’s family was not present, according to Palestinian officials.
It is 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 Suha Arafat.
Arafat's belongings were analysed by the Institut de Radiophysique, 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 his 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.
Describing the complexity of the task facing investigators in an interview to Al Jazeera on Tuesday, Dr Rebecca Hsu, a forensic pathologist based in the US state of Arizona, said: "Exhumations are always extremely difficult. You are dealing with the added problem that a time period has passed."
Hsu said Investigators "must be very cautious" in how the body is removed and how samples are obtained "so that nothing that was not present initially is then added and perhaps mistaken for the original damage".
'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 Suha Arafat earlier this month. Tirawi also said that the investigators had 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 PA.
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.