PARIS - New scientific evidence supports the theory that Napoleon Bonaparte was poisoned with arsenic during his second exile, a French toxicologist said Thursday.

Pascal Kintz said he found traces of the poison in two strands of the French emperor's hair, supporting the conclusions of past tests.

Napoleon died May 5, 1821, on the island of St. Helena, where he had been banished after his defeat at Waterloo. He was 52.

The official cause of death is stomach cancer.

Kintz did the tests at the request of the head of the International Napoleonic Society, Ben Weider. Weider claims Napoleon died of arsenic, arguing the British and French wanted to ensure he would not make a second comeback, as he had done after his exile on the island of Elba.

Conspiracy theories took on new seriousness a decade ago after the FBI and Britain's Scotland Yard discovered that clippings of Napoleon's hair were tinged with poison.

Kintz and colleagues said they previously examined and dismissed the possibility that the traces of poison could have come from other sources such as seafood.

"I'm simply saying that the arsenic found in his hair is mineral - thus, there was poisoning," Kintz told a Paris news conference on Thursday.

The strands studied by Kintz were purchased at a Paris auction 30 years ago. In other tests, Napoleon's hair samples came from a number of sources to ensure accuracy.

Weider hopes to gain access to Napoleon's body, buried in the gilded Invalides monument in Paris.