American air safety experts were sent to assist Canadian investigators, who had primary responsibility for the recovery operations and the investigation.

But a few days earlier, Canadian investigators had told the F.B.I. that they had not been able to link him to the terrorist group.

She said that the Hong Kong and Canadian investigators found that a collection of factors had to converge to cause the outbreak.

In studies with mice and pigs, Canadian investigators have found that antidepressants can act as tumor promoters, hastening the growth of nascent malignancies.

The Americans apparently were acting on bad information fed to them by Canadian investigators.

Canadian investigators say they believe that the first four shootings are related.

In the end, however, the Canadian investigators recruited enough women so that statistically they would have seen a survival effect if there had been one.

On Thursday a federal judge reviewed evidence from Canadian investigators who asserted that Mr. Sayegh was a threat to national security.

Canadian investigators tracked him down through the Internet.

He said the questions were almost identical to those from Canadian investigators in 2000.