But, several investigators cautioned, the disclosure of the bomb-sniffing dog test does not rule out the validity of the chemical traces, either.

But the investigators caution that these gains were accompanied by serious adverse side effects in nearly half the subjects, who developed pre-diabetes or diabetes, aching joints and swollen tissues.

But investigators cautioned it was not likely to lead to genetic screening.

The Pakistani investigator cautioned that tracing anyone's movements in Karachi, a sprawling urban labyrinth of 16 million people, can be next to impossible.

Military investigators specifically cautioned them not to implicate any higher ranking officers, one guardsman said.

And some outside investigators caution that they would like to examine more of the records before deciding what caused the break.

No one connected with the attorney general's investigation has accused Mr. Israel of doing anything wrong, and investigators caution that there may be a reasonable explanation.

That part of the investigation is at the earliest stages, and investigators caution that no link may be found.

But the investigators cautioned that they had received no hard evidence of the payments.

But even as investigators have cautioned against prematurely linking the cases, they acknowledged a number of similarities.