Story highlights The probe was launched after Arafat's widow lodged a formal complaint for murder

High levels of a radioactive substance have been found on some of Arafat's belongings

A member of the Palestine Liberation Organization welcomes the probe

Arafat died at age 75 at a Paris military hospital after suffering a brain hemorrhage

French authorities have opened a murder inquiry into the 2004 death of then-Palestinian leader Yasser Arafat, a prosecution official said Tuesday.

The inquiry comes after last month's discovery of high levels of a radioactive substance on some of Arafat's personal belongings. His successor, Palestinian Authority President Mahmoud Abbas, subsequently approved the exhumation of Arafat's body

Caroline Chassain, secretary general of the prosecutor's office in the Paris suburb of Nanterre, told CNN the inquiry was launched after Arafat's widow, Suha Arafat, lodged a formal legal complaint for murder.

Hanan Ashrawi, of the Palestine Liberation Organization's executive committee, welcomed the inquiry, saying it is of high importance.

"We believe the death of President Arafat was not a natural death, and also believe there should be a forensic and criminal investigation," she said.

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Ashrawi said the Palestinian people needed closure and that there should be "real accountability for those responsible" for Arafat's death.

A Palestinian investigation has already been set up, she said, but it is not yet clear when the exhumation will be carried out. Medical experts from Switzerland are expected to travel to Ramallah to take samples from the body.

Arafat died at age 75 at a Paris military hospital after he suffered a brain hemorrhage and slipped into a coma.

Palestinian officials said in the days before his death that Arafat had a blood disorder -- though they ruled out leukemia -- and digestive problems.

Rumors of poisoning circulated at the time, but Palestinian officials denied them, and then-Palestinian Foreign Minister Nabil Sha'ath said he "totally" ruled them out.

A Swiss doctor said last month that investigators had found high levels of toxic polonium-210 on some of Arafat's belongings, though it does not confirm he suffered radiation poisoning.

Francois Bochud, director of the Institut de Radiophysique in Lausanne, Switzerland, said his researchers had tested Arafat's toothbrush, clothing and keffiyeh, the distinctive black-and-white headscarf he often wore.

A body fluid stain contained 180 megabecquerels per liter of the radioactive isotope, while a typical sample would contain 5 megabecquerels per liter, Bochud said. A becquerel is a unit of measurement of radioactivity.

The fabric of Arafat's clothing, without body fluid, contained less than 10 megabecquerels per liter, Bochud said.