The FBI investigation into whether classified information was passed to the Israeli government is focused on a Pentagon analyst who has served as an Air Force reservist in Israel, and the probe has been broadened in recent days to include interviews at the State and Defense departments and with Middle Eastern affairs specialists outside government, officials and others familiar with the inquiry said yesterday.

At the center of the investigation, sources said, is Lawrence A. Franklin, a career analyst at the Defense Intelligence Agency who specializes in Iran and has served in the Air Force Reserve, rising to colonel. Early in the Bush administration, Franklin moved from the DIA to the Pentagon's policy branch headed by Undersecretary Douglas J. Feith, where he continued his work on Iranian affairs.

Officials and colleagues said yesterday that Franklin had traveled to Israel, including during duty in the Air Force Reserve, where he served as a specialist in foreign political-military affairs. He may have been based at the U.S. Embassy in Tel Aviv on those tours, said a former co-worker at the DIA, but was never permanently assigned there.

Messages left at Franklin's Pentagon office were not returned yesterday, and nobody answered the door at his house in West Virginia. No one has been charged in the case.

FBI officials have been quietly investigating for months whether Franklin gave classified information -- which officials said included a draft of a presidential directive on U.S. policies toward Iran -- to two Israeli lobbyists here who are alleged to have passed it on to the Israeli government. Officials said it was not yet clear whether the probe would become an espionage case or perhaps would result in lesser charges such as improper release of classified information or mishandling of government documents.

On Friday, Pentagon officials said Franklin was not in a position to have significant influence over U.S. policy. "The Defense Department has been cooperating with the Department of Justice for an extended period of time," a Pentagon statement said. "It is the DOD's understanding that the investigation within DOD is very limited in its scope."

At the Pentagon and elsewhere in Washington yesterday, people touched by the case said they were baffled by aspects of it.

Colleagues said they were stunned to hear Franklin was suspected of giving secret information to a foreign government. And foreign policy specialists said they were skeptical that the pro-Israel group under FBI scrutiny, the American Israel Public Affairs Committee, would jeopardize its work with classified documents from a midlevel bureaucrat when it could find out almost anything it wanted to by calling top officials in the Bush administration.

"The whole thing makes no sense to me," said Dennis Ross, special envoy on the Arab-Israeli peace process in the first Bush administration and the Clinton presidency. "The Israelis have access to all sorts of people. They have access in Congress and in the administration. They have people who talk about these things," said Ross, now a senior fellow at the Washington Institute for Near East Policy.

Prime Minister Ariel Sharon's office issued a statement yesterday saying Israel was not involved in the matter and conducts no espionage in the United States. AIPAC has strongly denied any wrongdoing and said it is "cooperating fully" with the probe.

The FBI investigation was touched off months ago when a series of e-mails was brought to investigators' attention, said a U.S. official familiar with the case. The investigation moved into high gear in recent days, another official said. On Friday, Justice Department officials briefed some Pentagon officials about the state of the inquiry.

"I think they are at the end of their investigation and beginning to brief people in the chain of command, partly to make sure that the acts weren't authorized," one official said.

Pentagon co-workers expressed shock at the news. "It's totally astonishing to all of us who knew him," said a Defense Department co-worker who asked not to be identified because of the investigation. "He is a career guy, a mild-mannered professional. No one would think of him as evil or devious."

Franklin works in the office of William J. Luti, deputy undersecretary of defense for Near Eastern and South Asian affairs. For years a bureaucratic backwater, the office has been in the thick of the action since 2001 because it formulates Pentagon policy on Iraq. It played a central role as the U.S. military prepared for the spring 2003 invasion and since then as the Pentagon has overseen the occupation.

Luti's office is part of the policy operation under Feith.

Feith has been a controversial figure in U.S.-Israeli affairs since the mid-1990s, when he was part of a study group of American conservatives, then out of government, who urged Israel's then prime minister, Binyamin Netanyahu, to abandon the Oslo peace accords and reject the basis for them -- that Israel should give up land in exchange for peace.

More recently, Feith has been a target of criticism from Democrats who claim that two offices in his branch -- the Office of Special Plans, headed by Luti, and the Counterterrorism Evaluation Group -- sought to manipulate intelligence to improve the Bush administration's case for war against Iraq. House and Senate intelligence committee investigators found no evidence for allegations that the Pentagon offices tried to bypass the CIA or had a major impact on the prewar debate. But in the Senate panel's report on prewar intelligence, three Democratic senators -- John D. Rockefeller IV (W.Va.), Carl M. Levin (Mich.), and Richard J. Durbin (Ill.) -- specifically criticized Feith's operation.

In Kearneysville, W.Va., about 80 miles from the Pentagon, neighbors of the Franklins interviewed yesterday said they did not know the family well. Though nobody answered the door, voices were heard in the house, which had a "God Bless Our Troops" sticker and an American flag in the window.

People who know Franklin from different phases of his life offered contrasting accounts of his political views.

A U.S. government official familiar with the investigation said Franklin was very outwardly supportive of Israel, for example. But a former co-worker at the DIA disputed that characterization, saying that he did not recall in years of working with him any strong political statements about Israel or anything else. Franklin, he said, was a solid, competent analyst specializing in Iranian political affairs, especially the views of top leaders and the course of opposition movements.

In February 2000, Franklin wrote an op-ed piece for the Wall Street Journal's European edition that was sharply critical of Iranian President Mohammad Khatami, arguing that the leader was launching a "charm offensive" that was simply a "ruse" to make the Iranian government look better to Westerners while it continued to abuse human rights.

Details of Franklin's Air Force service, and especially his time in Israel, could not be learned yesterday. A spokesman for the U.S. Embassy in Tel Aviv declined to comment.

In Israel yesterday, Sharon's office issued a statement. "Israel does not engage in intelligence activities in the U.S. We deny all these reports," the statement said, according to the Associated Press. That followed a strong statement Friday by the Israeli Embassy in Washington denying any wrongdoing.

One Israeli official familiar with the situation said yesterday that his government had checked "every organ here" to make sure that no part of government was involved. "We checked everything possible, and there's absolutely nothing. It's a non-event, from the Israeli point of view. Someone leaked this to [hurt] . . . the president, AIPAC and the Jews on the eve of the Republican convention," he speculated.

He added that Israel would not have been involved in such activities, "because we have a trauma here in Israel. It's called Pollard."

That was a reference to the case in which a U.S. Navy intelligence analyst, Jonathan J. Pollard, admitted in 1987 to selling state secrets to Israel. Pollard was sentenced to life in prison, and Israeli officials have said since then they do not conduct espionage against the United States.

At AIPAC, spokesman Josh Block said the organization had no comment yesterday beyond its Friday statement that the organization and its employees denied any wrongdoing and were cooperating with the government. A former AIPAC employee also said he was baffled by the news of the FBI investigation. "I have a hard time figuring out what this is about," he said. If the Israelis or their supporters want to know about deliberations in the Bush administration, he said, "all they have to do is take people to lunch."

Others in Washington, however, maintained that Israel does present a problem for the United States in certain aspects of intelligence, such as sensitive defense technologies and Iran policy.

Israel sees Iran as the single biggest threat to its existence, and so closely monitors all possible moves in Washington's Iranian policy -- especially as the Bush administration presses Tehran to disclose more about the state of its nuclear program.

One former State Department officer recalled being told that U.S. government experts considered the countries whose spying most threatened the United States were Russia, South Korea and Israel. "I also know from my time in Jerusalem that official U.S. visitors to Israel were warned about the counterintelligence threat from Israel," he said.

Taking a slightly different view, others speculated that the very closeness of the relationship between the United States and Israeli governments -- and especially the tight connections between the Israelis and Feith's policy office -- may have led officials to become sloppy about rules barring release of sensitive information.

Staff writers John Ward Anderson in Jerusalem, Dan Eggen, Amit R. Paley, Steven Ginsberg and Jerry Markon in Washington and staff researcher Madonna Lebling contributed to this report.