The FBI has never found the individual who allegedly asked two Yemenis to take photos of federal buildings in downtown New York in May 2001, an episode that was mentioned in an intelligence report given President Bush little more than a month before the attacks on the World Trade Center, according to government officials.

The two Yemenis were questioned on May 30, 2001, by Immigration and Naturalization Service agents, and their camera was confiscated after guards saw them taking photos of 26 Federal Plaza and surrounding buildings, including one that housed the FBI's counterterrorism unit in New York.

Federal officials developed the film and found the images showed the plaza and surrounding buildings, plus the street. When FBI agents subsequently questioned the two men, they said they took the photos for a friend in Indianapolis who had never visited New York. The FBI has never located the Yemeni friend, who was in the United States under an assumed name with false documents.

Federal officials at the time were on alert because one day earlier, in one of the courthouses photographed, six men had been found guilty on a number of counts in connection with the bombings of the U.S. embassies in Nairobi, Kenya, and Dar es Salaam, Tanzania, an attack linked to al Qaeda. A terrorist alert had been put out that day by the State Department, although the government said at the time it was not aware of any specific threat in response to the verdicts.

The President's Daily Brief (PDB) for Aug. 6, 2001, the highly classified intelligence report prepared by CIA for President Bush and top officials, contained a short section titled, "Bin Ladin Determined To Strike in US." Along with some past material about previous threats by the al Qaeda leader, the report referred to the FBI investigating "suspicious activity in this country consistent with the preparations for hijackings or other types of attacks, including recent surveillance of federal buildings in New York."

At the time of the public release of the briefing document last month, a White House fact sheet said the FBI had "interviewed the men and determined that their conduct was consistent with tourist activity and the FBI's investigation identified no link to terrorism."

Neither the fact sheet nor two White House officials who briefed reporters April 9 mentioned that a third Yemeni was involved.

Within a few weeks of the May 30, 2001, incident, the FBI concluded that the two Yemeni men had no connection to terrorists and appeared to be taking tourist photos, according to a senior FBI official, who declined to be identified because he was discussing an ongoing investigation.

But the official also acknowledged that the third man, who had been working in the Indianapolis area under the assumed name Mohammed Hassan Abadi, has never been located or interviewed. The FBI does not know the man's real name, but it does have a photograph of him and has found no links between his assumed name or photograph and terrorist groups or individuals, the official said.

The FBI official gave this account of the incident and its aftermath:

On May 30, a Yemeni native who had been living in Brooklyn, N.Y., for more than two decades visited the federal building with a friend, who had been working in Indiana but had returned to New York for an appointment with immigration officers.

Guards with the Federal Protective Service, then part of the General Services Administration, noticed the Indiana man taking photographs of the federal building and others in the area. They confiscated his disposable camera, and the pair were interviewed by an FBI agent.

The Indiana man told the FBI agent that he was taking the photographs for Abadi, also a Yemeni national, because he wanted to see pictures of Manhattan. The two men were released, but authorities became concerned when the film was developed and was found to include four photographs of 26 Federal Plaza and neighboring buildings.

By the time FBI agents went looking for Abadi in Indiana, he had fled, without collecting his last paycheck at the factory where he worked. Agents concluded that his friend, who had taken the photographs, told him about the encounter with federal agents and that Abadi fled because he was in the country illegally.

The official said Abadi's photograph and assumed name have been widely circulated among counterterrorism agents and law enforcement officials.

"We don't know for sure. But we've never been able to determine any link to anything suspicious or out of the ordinary," the FBI official said. "He was out of status and had reason to be concerned about the government."

The official said the FBI's concerns about the case were largely eliminated within weeks, but the incident "took on a life of its own" and resulted in the anecdote being included in the presidential briefing. An FBI analyst supplied the information to the CIA analyst who prepared the briefing document, apparently taking it from a report related to security concerns in Lower Manhattan that summer, the official said.

The two Yemenis who had visited the federal complex that day remain in the United States and have been interviewed on more than one occasion since the Sept. 11, 2001, attacks, the official said, but neither is suspected of terrorist links.

"The two photo takers have been cooperative ever since," the official said. "They've gone about their lives in exactly the same way."

A senior intelligence official, who would speak about the ongoing investigation only with a guarantee of anonymity, said there were still some questions within the intelligence community about the "third man," and the tourist story was "open to interpretation." He added that the FBI still says its interpretation was correct, and officials expect that the issue may be discussed during upcoming hearings in New York of the commission investigating the Sept. 11 terrorist attacks.