Already, the FBI--along with parallel probes by House and Senate investigators--have turned up significant and potentially embarrassing new details about how the documents came into the possession of the U.S. government in the first place and the apparent mishandling of the material by officials at both CIA and State once they arrived, sources say.

In a bureaucratic snafu that some investigators are calling inexplicable, the CIA never arranged to obtain the forged documents until February 2003--nearly four months after they had been delivered to the U.S. Embassy in Rome and been passed along to the State Department.

The FBI's principal focus, sources said, is to determine who forged the documents and why. Were they part of an orchestrated covert operation--by Iraqi exiles or others--designed to build international support for a war to topple Saddam?

Or were the documents, as some investigators suspect, a scam perpetrated by con men who sought to make money off the material by exploiting the widely known American interest in finding damaging evidence about the Iraqi regime?

Either way, answer is crucial. "This was high-stakes poker," said an aide to Rockefeller, whose office is closely monitoring the probe. "Whoever did this was messing with the minds of the American people."

The new details about the handling of the documents may prove just as significant, however, and are likely to be a focus of questioning today when CIA director George Tenet appears in closed session before the Senate Intelligence Committee. Although far from conclusive, the new information points to a larger problem that has been a consistent theme in major terrorism and intelligence failures in the past: a lack of communication and ingrained bureaucratic resistance to the sharing of information.