After more than two weeks of around-the-clock investigation into the September 11th attacks on the World Trade Center and the Pentagon, the American intelligence community remains confused, divided, and unsure about how the terrorists operated, how many there were, and what they might do next. It was that lack of solid information, government officials told me, that was the key factor behind the Bush Administration’s decision last week not to issue a promised white paper listing the evidence linking Osama bin Laden’s organization to the attacks.

There is consensus within the government on two issues: the terrorist attacks were brilliantly planned and executed, and the intelligence community was in no way prepared to stop them. One bureaucratic victim, the officials said, may be George Tenet, the director of the Central Intelligence Agency, whose resignation is considered a necessity by many in the Administration. “The system is after Tenet,” one senior officer told me. “It wants to get rid of him.”

The investigators are now split into at least two factions. One, centered in the F.B.I., believes that the terrorists may not have been “a cohesive group,” as one involved official put it, before they started training and working together on this operation. “These guys look like a pickup basketball team,” he said. “A bunch of guys who got together.” The F.B.I. is still trying to sort out the identities and backgrounds of the hijackers. The fact is, the official acknowledged, “we don’t know much about them.”

These investigators suspect that the suicide teams were simply lucky. “In your wildest dreams, do you think they thought they’d be able to pull off four hijackings?” the official asked. “Just taking out one jet and getting it into the ground would have been a success. These are not supermen.” He explained that the most important advantage the hijackers had, aside from the element of surprise, was history: in the past, most hijackings had ended up safely on the ground at a Third World airport, so pilots had been trained to coöperate.

Another view, centered in the Pentagon and the C.I.A., credits the hijackers with years of advance planning and practice, and a deliberate after-the-fact disinformation campaign. “These guys were below everybody’s radar—they’re professionals,” an official said. “There’s no more than five or six in a cell. Three men will know the plan; three won’t know. They’ve been ‘sleeping’ out there for years and years.” One military planner told me that many of his colleagues believe that the terrorists “went to ground and pulled phone lines” well before September 11th—that is, concealed traces of their activities. It is widely believed that the terrorists had a support team, and the fact that the F.B.I. has been unable to track down fellow-conspirators who were left behind in the United States is seen as further evidence of careful planning. “Look,” one person familiar with the investigation said. “If it were as simple and straightforward as a lucky one-off oddball operation, then the seeds of confusion would not have been sown as they were.”

Many of the investigators believe that some of the initial clues that were uncovered about the terrorists’ identities and preparations, such as flight manuals, were meant to be found. A former high-level intelligence official told me, “Whatever trail was left was left deliberately—for the F.B.I. to chase.”

In interviews over the past two weeks, a number of intelligence officials have raised questions about Osama bin Laden’s capabilities. “This guy sits in a cave in Afghanistan and he’s running this operation?” one C.I.A. official asked. “It’s so huge. He couldn’t have done it alone.” A senior military officer told me that because of the visas and other documentation needed to infiltrate team members into the United States a major foreign intelligence service might also have been involved. “To get somebody to fly an airplane—to kill himself,” the official added, further suggests that “somebody paid his family a hell of a lot of money.”

”These people are not necessarily all from bin Laden,” a Justice Department official told me. “We’re still running a lot of stuff out,” he said, adding that the F.B.I. has been inundated with leads. On September 23rd, Secretary of State Colin Powell told a television interviewer that “we will put before the world, the American people, a persuasive case” showing that bin Laden was responsible for the attacks. But the widely anticipated white paper could not be published, the Justice Department official said, for lack of hard facts. “There was not enough to make a sale.”

The Administration justified the delay by telling the press that most of the information was classified and could not yet be released. Last week, however, a senior C.I.A. official confirmed that the intelligence community had not yet developed a significant amount of solid information about the terrorists’ operations, financing, and planning. “One day, we’ll know, but at the moment we don’t know,” the official said.

”To me,” he added, “the scariest thing is that these guys”—the terrorists—”got the first one free. They knew that the standard operating procedure in an aircraft hijacking was to play for time. And they knew for sure that after this the security on airplanes was going to go way up. So whatever they’ve planned for the next round they had in place already.”

The concern about a second attack was repeated by others involved in the investigation. Some in the F.B.I. now suspect that the terrorists are following a war plan devised by the convicted conspirator Ramzi Ahmed Yousef, who is believed to have been the mastermind of the 1993 World Trade Center bombing. Yousef was involved in plans that called for, among other things, the releasing of poisons in the air and the bombing of the tunnels between New York City and New Jersey. The government’s concern about the potential threat from hazardous-waste haulers was heightened by the Yousef case.

”Do they go chem/bio in one, two, or three years?” one senior general asked rhetorically. “We must now make a difficult transition from reliance on law enforcement to the preëmptive. That part is hard. Can we recruit enough good people?” In recent years, he said, “we’ve been hiring kids out of college who are computer geeks.” He continued, “This is about going back to deep, hard dirty work, with tough people going down dark alleys with good instincts.”

Today’s C.I.A. is not up to the job. Since the breakup of the Soviet Union, in 1991, the C.I.A. has become increasingly bureaucratic and unwilling to take risks, and has promoted officers who shared such values. (“The consciousness of kind,” one former officer says.) It has steadily reduced its reliance on overseas human intelligence and cut the number of case officers abroad—members of the clandestine service, now known formally as the Directorate of Operations, or D.O., whose mission is to recruit spies. (It used to be called the “dirty tricks” department.) Instead, the agency has relied on liaison relationships—reports from friendly intelligence services and police departments around the world—and on technical collection systems.

It won’t be easy to put agents back in the field. During the Cold War, the agency’s most important mission was to recruit spies from within the Soviet Union’s military and its diplomatic corps. C.I.A. agents were assigned as diplomatic or cultural officers at American embassies in major cities, and much of their work could be done at diplomatic functions and other social events. For an agent with such cover, the consequence of being exposed was usually nothing more than expulsion from the host country and temporary reassignment to a desk in Washington. Today, in Afghanistan, or anywhere in the Middle East or South Asia, a C.I.A. operative would have to speak the local language and be able to blend in. The operative should seemingly have nothing to do with any Americans, or with the American embassy, if there is one. The status is known inside the agency as “nonofficial cover,” or NOC. Exposure could mean death.