Committee members said they were shown documents defending General Pollari, including a copy of a classified letter from Robert S. Muller III, the director of the F.B.I., dated July 20, which praised Italy's cooperation with the bureau.

In Washington, an official at the bureau confirmed the substance of the letter, whose contents were first reported Tuesday in the leftist newspaper L'Unit\ufffd. The letter stated that Italy's cooperation proved the bureau's theory that the false documents were produced and disseminated by one or more people for personal profit, and ruled out the possibility that the Italian service had intended to influence American policy, the newspaper said.

As a result, the letter said, according to both the F.B.I. official and L'Unit\ufffd, the bureau had closed its investigation into the origin of the documents.

One striking aspect of the FBI's investigation is that, at least as of this week, Martino has told associates he has never even been interviewed by the bureau-despite the fact that he was publicly identified by the Financial Times of London as the source of the documents more than six weeks ago and was subsequently flown to New York City by CBS to be interviewed for the "60 Minutes" report.

A U.S. law-enforcement official said the FBI is seeking to interview Martino, but has not yet received permission to do so from the Italian government. The official declined to comment on other aspects of the investigation.