A team of Swiss investigators visited the West Bank grave of late Palestinian leader Yasser Arafat Monday to determine how best to dig up remains and extract samples ahead of their exhumation later this month, a Palestinian official said.

The Swiss team, one of two groups set to conduct parallel probes into Arafat's 2004 death, spent an hour inspecting the tomb, located in a mausoleum outside Palestinian government headquarters in Ramallah. A Western diplomat, who spoke on condition of anonymity because the investigation is ongoing, said the exhumation would most likely take place Nov. 26.

Tawfik Tirawi, the head of the Palestinian committee investigating the death, said Monday's visit was meant "to check the place" ahead of the exhumation. The Swiss team is expected to return at the end of the month along with French investigators to exhume the body, and will be allowed only one chance to withdraw samples from the remains.

The French and Swiss teams are acting separately on behalf of Arafat's widow Suha Arafat and the Palestinian Authority, who each had misgivings about the other's investigation. The late leader's wife and the Palestinian Authority have a history of rocky relations, and Palestinian officials have complained that they felt Suha Arafat was forcing an investigation on them.

The new probes into Arafat's death come after a Swiss lab recently discovered traces of polonium-210, a deadly radioactive isotope, on clothes said to be his, which sparked new accusations that he was poisoned.

Arafat's death in a French hospital in November 2004 has remained a mystery for many. While the immediate cause of death was a stroke, the underlying source of an illness he suffered in his final weeks has never been clear, leading to persistent conspiracy theories that he had cancer, AIDS or was poisoned.

Many in the Arab world believe Arafat, the face of the Palestinian independence struggle for four decades, was killed by Israel. Israel, which saw Arafat as an obstacle to peace, vehemently denies the charge.

There is no guarantee the exhumation will solve the mystery. Polonium-210 is known to rapidly decompose, and experts are divided over whether any remaining samples will be sufficient for testing.