The missed signals now haunt a generation of U.S. intelligence and law enforcement officials, who realize that their efforts to track terrorists linked to Osama bin Laden had been undermined at times by bungled investigations and bureaucratic rivalries.
U.S. officials insist they have successfully halted numerous terrorist attacks at home and abroad in recent years, preventing thousands of deaths.
But "every time we caught them and thwarted an attack, they learned from it," said Michael Swetnam, a terrorism expert and consultant to U.S. intelligence agencies. "This time, they avoided the mistakes they made before."
The question now is how well U.S. law enforcement and intelligence agencies have learned from their mistakes.
Evidence has been neglected. Earlier this year, for example, French experts gave an in-depth report on Bin Laden's financial network to a senior FBI official, according to a source close to the French intelligence community. A month later, the FBI official admitted to his French colleagues that the document still had not been translated into English.
Patterns have not been detected. The FBI had known for at least three years, for example, that at least two Bin Laden operatives trained to be pilots in the United States. One of the pilots, Essam al Ridi, a naturalized U.S. citizen of Egyptian descent, even purchased a used military aircraft in Arizona for Bin Laden in 1993. He flew the Saber-40 twin-engine passenger jet to Sudan after buying it for $210,000.
Federal authorities also knew that Ramzi Yousef, who masterminded the 1993 truck bombing of the World Trade Center, later planned to blow up 12 United Airlines, Delta Air Lines and Northwest Airlines jumbo jets over the Pacific Ocean. After the plot was uncovered in 1995, a co-conspirator, Abdul Hakim Murad, told police in the Philippines that he had hoped to hijack a passenger plane and crash it into CIA headquarters outside Washington. Murad had attended four U.S. flight schools.
Yet no surveillance was in place to scrutinize aspiring pilots or to raise a warning flag when the men who would eventually hijack four jetliners Sept. 11 trained at flight schools around the country.
Agents have been slow to recognize suspects. After the 1993 attack on the World Trade Center, Abdul Rahman Yasin was held and questioned by the FBI--and then allowed to leave the country. President Bush last week named Yasin one of the country's 22 "most wanted" terrorists in connection with his alleged role in that attack. Another would-be bomber in that case used prison telephones 20 times to contact fellow plotters.
And, in the weeks before Sept. 11, the FBI made only a routine attempt to find two men flagged by the CIA for suspected ties to terrorists. The men later helped hijack the airliner that crashed into the Pentagon.
Bush said at his news conference Thursday that the FBI "must think differently" than it has in the past. "In a post-Cold War era, they were still chasing spies. Nothing wrong with that, except we have a new enemy."
The CIA faces a similar challenge. The U.S. satellites and other high-tech surveillance systems were designed to snoop on Cold War governments and armies, not small bands of religious fanatics.
Bin Laden "was a very small blip" after he launched Al Qaeda in 1989, said William H. Webster, a former head of the FBI and the CIA. Said another former official: "Bin Laden was declaring war on us, but we didn't get it."
It wasn't until 1996 that a special federal grand jury convened in the southern district of New York to investigate what prosecutors called "the structure, goals and operational status of Al Qaeda worldwide; whether Al Qaeda was involved in planning crimes against American interests and, if so, which ones."
Washington finally set up a secret interagency task force in 1998, led by the CIA, to track and capture Bin Laden after two U.S. embassies in Africa were hit by suicide bombers.
But that effort has been hamstrung by turf battles among the federal agencies. Although cooperation has improved, rifts remain deep between intelligence and law enforcement officials.
Competing missions are partly to blame. Intelligence agencies seek to spy on suspected terrorists and prevent future attacks; they need to cloak their sources to do it. The FBI and federal prosecutors seek to expose and punish those who carry out terror attacks; they need public witnesses and documents to do it.
U.S. law doesn't always help. If a terrorist enters the United States, the National Security Agency, which intercepts communications overseas, must stop their efforts at the border, as they are barred from spying within the United States.
"You're trying to track somebody; the agency [NSA] may have locked on the guy's cell phone overseas. As soon as he shows up in the United States, they have to turn that off," a former federal prosecutor in New York explained.
The miscommunications extend across borders as well. French officials, for example, privately criticized U.S. authorities for ignoring their warnings about a Montreal cell of Algerian terrorists, even as members planned to bomb Los Angeles International Airport and other sites during New Year's celebrations in December 1999. The plot was discovered only when one of the bombers panicked and ran at the U.S. border.
And in February, the U.S. Embassy in London granted a student visa to an unemployed 33-year-old French Moroccan man, Habib Zacarias Moussaoui, even though he was on a special French immigration watch list of suspected Islamic extremists. Moussaoui was detained Aug. 17 on immigration charges after he allegedly told a Minnesota flight school that he wanted to learn to steer jumbo jets, but not learn to land them. Moussaoui remains in FBI custody in New York as a material witness while investigators try to determine whether he was involved with the skyjackers or any other terrorist plot.
"There was something there that the FBI could have done more with, a warning signal that was missed," a French official said.
U.S. officials say the missed signals seem more important in hindsight. They did not miss any specific warning about the events of Sept. 11, they say, because there wasn't one.
"The idea of commandeering an aircraft and crashing it into the ground and causing high casualties, sure we've thought of it," said Paul Pillar, the former deputy director of the CIA's counter-terrorist center. "But in terms of specific tip-offs to Sept. 11, no, we had nothing." Bill Harlow, a CIA spokesman, agreed: "There's always lots of stuff that seems more meaningful now than before an event. But is there something that suggests they were going to fly an airplane or two into the World Trade Center? No. There was nothing specific about time, method or place."
Still, Bin Laden hasn't been shy about sharing his game plan.
In the summer of 1998, he sent a fax from Afghanistan to Sheik Omar Bakri Mohammed, a London-based Muslim cleric who had dubbed himself the "mouth, eyes and ears of Osama bin Laden." Bakri later released what he called Bin Laden's four specific objectives for a holy war against the U.S.
"Bring down their airliners," read the instruction. "Prevent the safe passage of their ships. Occupy their embassies. Force the closure of their companies and banks."
It is fair to say he has achieved at least some of his goals. It also is fair to say U.S. authorities had the plotters in their grasp--or in their sights--in almost every case. Those missed opportunities thus form the backdrop to the country's current war on terror.
"Force the Closure of Their Companies"
The U.S. government was pretty sure Ahmad Mohammad Ajaj was a terrorist from the moment he stepped foot on U.S. soil.
The 26-year-old Palestinian's suitcases were stuffed with fake passports, fake IDs and a cheat sheet on how to lie to U.S. immigration inspectors.
And then there were the two handwritten notebooks filled with bomb recipes, the six bomb-making manuals, the four how-to videotapes concerning weaponry and the advanced guide to surveillance training.
But all federal prosecutors charged him with after Ajaj flew into New York's John F. Kennedy International Airport from Pakistan on Sept. 1, 1992, was passport fraud--a crude, photo paste job on a stolen Swedish passport at that.
The possession of terrorist literature, "believe it or not, was not a crime," said Eric Bernstein, the former prosecutor who handled the case. Ajaj was sentenced to six months in prison for passport violations.
Over the next five months Ajaj would speak frequently over a prison phone with Ramzi Ahmed Yousef, who had flown with him to New York. Yousef left the country Feb. 26, 1993, 12 hours after his bomb killed six, injured more than a thousand and caused $550 million worth of damage in the first World Trade Center attack.
Although prison phone calls are taped, no one monitored Ajaj's 20 calls to Yousef and other conspirators--or tried to translate them from Arabic--until long after the blast. And no one traced his plane ticket until after the blast to determine that he and Yousef had sat together on the first leg of their journey to New York.
The result: No one figured out Ajaj's plot or identified his co-conspirators until after the attack. Indeed, Ajaj was released from prison three days after the explosion and only later was rearrested and sentenced to more than 100 years in prison for his role.
"I think what we've gotten really good at is going back and re-creating the trail after an incident," said Henry DePippo, who eventually prosecuted Ajaj for conspiracy in the bombing. "We need to attack these cases with the same energy before a terrorist attack occurs."
For starters, it would have helped to know just what Ajaj actually had in his Arabic-language "terrorist kit." But his manuals had not been "disseminated to the intelligence community for full translation and exploitation of the information," nine years after they were seized, L. Paul Bremer III, head of the National Commission on Terrorism, told a Senate committee in June.
"Occupy Their Embassies"
At first blush, the raid on a modest house in the Kenyan capital of Nairobi on Aug. 21, 1997, was a huge success.
Moving quietly, Kenyan police and veteran FBI agent Daniel Coleman found a trove of computer records and documents belonging to Wadih El-Hage, the former "personal secretary" to Bin Laden, a top Al Qaeda operative and a suspected "money conduit" for terrorist attacks. He was due back that day from visiting Bin Laden in Afghanistan.
Authorities found crucial data about Harun Fazhl, a Bin Laden operative who directed the operations of a secret cell of terrorists plotting at that moment to bomb U.S. embassies in Kenya and Tanzania.
Despite the intelligence coup, the two embassies were gutted by suicide truck bombs less than a year later; 224 people died, including 12 Americans.
The CIA and the FBI missed key opportunities to prevent the blasts. They knew from wiretaps on El-Hage's four Nairobi phones, as well as from the computer files they had seized, that Al Qaeda was forming a terror cell in the Kenyan capital. Indeed, U.S. agents had in hand the names and identities of some of the key Nairobi cell members who would rent the bomb factory, build the bomb, buy the bomb truck, brief the suicide bombers and even escort the bomb truck the day of the attack.
U.S. authorities nevertheless lagged several steps behind the embassy plotters. They still are behind: So far, 10 suspects, including El-Hage, have been convicted or have pleaded guilty or are in custody awaiting trial. But 13 others, including Bin Laden and Fazhl, are still at large. And last week, Bush included Fazhl on his "most wanted" list of suspected terrorists.
U.S. investigators "never systematically tried to run down the information they had," said Carl Herman, a lawyer for Mohamed Sadeek Odeh, one of four men convicted last summer in New York. "Maybe they didn't have the manpower. Maybe they felt it wasn't worth the effort."
Sam Schmidt, El-Hage's lawyer, said his client insisted that U.S. investigators and prosecutors "shared some responsibility for the tragedy." El-Hage contended the government was well aware a year before the embassy attacks "of Harun Fazhl's involvement in the 'Al Qaeda cell' in Nairobi," Schmidt said during a pretrial hearing.
Others say the CIA and the FBI missed crucial signals--or failed to understand the ones they had. "I don't think it's a problem with intelligence gathering," a lawyer familiar with the case said. "It's a problem with intelligence analysis."
To be sure, tracking cell members wasn't easy. They met regularly in mosques and on busy streets to throw off U.S. agents. They changed identities with false passports and visas. They moved sensitive documents from house to house to avoid detection.
On the other hand, they wandered in and out of the U.S. Embassy, scanning for weak points and undefended areas in the downtown building.
Bob Blitzer, who headed the FBI's international terrorism section until 1997, said the CIA didn't have enough field agents who spoke local languages and could blend in well enough to conduct close-up surveillance without being detected.
"One of our biggest problems is we still haven't found the key to penetrating those cells with human sources," Blitzer said.
Instead, U.S. agents relied heavily on high-tech surveillance, especially wiretaps and intercepts of satellite phone calls by Bin Laden and his lieutenants in Afghanistan.
The wiretaps and intercepts produced tens of thousands of pages of transcripts over two years. Yet they did little good. U.S. officials often didn't know who was speaking to whom.
"This wasn't like Mafia wiretaps, where you know who's calling the boss; who's who all the way down through the organization," a federal official familiar with the evidence said. "These were just voices. And in most cases, they were talking in code. It only became clear to us after the bombings."
The FBI discovered only then, for example, that Fazhl had replaced El-Hage as the mastermind and had directed the construction of the bomb.
"In a mob case, like a John Gotti case, you know where their hangouts are, where you can find them," the official said. "Here, we had only a limited feel for where they operated. We didn't have a line on all the players, and even the ones we did have, like Fazhl, it was unclear who they really were, where they were, and what they were up to day by day."
On Feb. 28, 1998, Bin Laden issued his most violent fatwa, expanding his holy war from U.S. soldiers to include U.S. civilians. That same day, Fazhl--who had been shuttling back and forth between Sudan and Kenya--bought a plane ticket for Nairobi.
The Kenyan capital would remain his base until the deadly explosions six months later. A defense lawyer argues that Fazhl should have been a key target for surveillance. "At that point, they should have picked him up full time," the lawyer insisted.
Nor is there any evidence that U.S. officials tried to work through the Kenyan government to break up the cell, rather than simply try to watch it. Police, after all, had assisted the FBI in the raid on El-Hage's home.
Instead, prosecutors hauled El-Hage before a federal grand jury in New York in September 1997. They pressured him to divulge what he knew about the plotting underway in Africa. He denied any knowledge.
Some defense lawyers compared the effort to pressure El-Hage to the tactics federal agents long have used to get Mafia underlings and drug traffickers to inform.
Al Qaeda does share some similarities with organized crime networks--an "omerta-like" emphasis on silence, a pyramidic hierarchy headed by a feared patriarchal figure, and an intermingling of legitimate and criminal enterprises. But Bin Laden's operatives have proved far more difficult to crack.
"What makes it so much harder to turn these guys is their blind dedication. No one in the mob is that willing to die for the cause," Blitzer said.
Not all the plotters died, of course. A week after the bombings, Fazhl flew to his Comoros Islands home. After a brief stay, he packed his clothes, travel documents and the passports belonging to the two suicide bombers.
Then, still as untouchable as he had been from the start, Fazhl followed his long-planned escape route by air to Pakistan and then into the rugged Afghan interior.
Among the victims of the attacks, anger against Al Queda is accompanied by bitter thoughts of the negligence that likely contributed to the tragedy.
A civil suit filed in Washington on behalf of the Kenyan victims is accompanied by documents showing that warnings that the building was "a soft target" went unheeded.
Prudence Bushnell, the U.S. ambassador to Kenya at the time of the bombings, wrote in a 1999 cable filed in the civil case: "Let me be blunt. Last year, when this mission raised the vulnerability of the previous embassy building, we received informal feedback that 'some' in Washington thought we were 'overreacting.' "
"Bring Down Their Airliners, Their Ships"
A CIA cable, or message, to FBI headquarters in Washington on Aug. 23 was not marked urgent. That was the first mistake.
Khalid Almihdhar and Nawaf Alhazmi, the cable advised, were in the United States, and Almihdhar might have evidence regarding last year's attack on the warship Cole in Yemen.
The Cole, a guided missile destroyer, was refueling in the Yemeni port of Aden on Oct. 12, 2000, when two men motored alongside in a small skiff and detonated hundreds of pounds of C-4 military explosive. The blast killed 17 sailors and nearly sank one of the U.S.' most modern warships.
The Pentagon had ordered no special security precautions for the Cole even though Yemen, Bin Laden's ancestral home, was a hotbed of militant Islam. U.S. intelligence had failed even to detect an attempted attack on another U.S. warship, the Sullivans, in Aden harbor 10 months earlier.
In that case, the attack boat was so overloaded with explosives that it sank in the harbor. The Cole attackers learned from that mistake.
After the Cole was hit, the FBI rushed dozens of agents to Yemen. But a yearlong investigation into the attack produced no indictments or prosecutions.
So the CIA cable should have triggered some action. A routine check of public records would have shown the men's last known addresses. A search of credit card transactions would have shown the purchase of airline tickets for Sept. 11. Neither apparently was done.
Instead, Almihdhar and Alhazmi were located only after they and three other conspirators had boarded American Airlines Flight 77 at Dulles International Airport outside Washington, seized control of the cockpit in flight and crashed the aircraft into the side of the Pentagon, killing 189 people.
It's impossible to know whether their capture before Sept. 11 would have provided enough information to unravel the conspiracy and thwart the deadly attacks. What is clear is that the foremost terrorist-hunting agencies in the U.S. missed a crucial opportunity.
The case dates from January 2000, when a group of men with suspected terrorist ties met in Kuala Lumpur, the capital of Malaysia. The CIA obtained a surveillance videotape about a month later that shows men arriving at the meeting, according to a U.S. intelligence official. The tape, he said, has no sound and wasn't viewed as very significant at the time.
"We knew who some of the people were, and worked on identifying them," the official said. "At the time, it was interesting video of a bunch of guys with shaky backgrounds getting together for unknown reasons."
Then, last summer, Yemeni authorities interrogated a suspect in the Cole case. He allegedly told them that an Al Qaeda operative had masterminded the attack. The same man already was being sought for questioning in the 1998 embassy bombing case.
"We go back and dust off everything we have on this guy," the intelligence official said. "We discover he's at this meeting in Kuala Lumpur a year or more before. We see who else is there. We determine that among the group is Khalid Almihdhar. That raises our interest in him."
The agency then did what it calls "link analysis." "We see who's there, who's meeting whom, where do they live, who did they travel with, who lived together, that sort of thing," a second intelligence official said.
One flight record showed Almihdhar traveling together with Alhazmi. The CIA also determined that Almihdhar had attended one of Bin Laden's terrorist training camps in Afghanistan.
On Aug. 21, the CIA recommended to the Immigration and Naturalization Service that both men be added to a special "watch list" kept to bar people with suspected terrorist ties from entering the United States. But the INS determined that both men already were here. On Aug. 23, the CIA sent the cable to the FBI.
Almihdhar had listed "Marriott hotel" as his planned address when he flew into New York, so the FBI started there. The New York field office got the case Aug. 27.
"Something like that is so common, it really doesn't have any bells attached to it," said a former FBI agent who worked counter-terrorism cases. "Just to say there are two possible Arab terrorists in the United States is ho-hum. You could have 10 more people you are working that day with hotter leads."
Another week passed. Shortly after Labor Day, the FBI in New York advised Washington that they could not find the two men. Agents went back to the INS. Almihdhar had listed a Sheraton hotel on his previous trip to Los Angeles. So the case was passed to the Los Angeles field office Sept. 9 or Sept. 10.
"It was like trying to find two rats in a crowded stadium. We didn't have a chance," one FBI agent recalled. Added another, "If we get word five weeks after someone gets into the country that they're here and we should find them, that's kind of a cold trail."
But a routine check of addresses and records from the California Department of Motor Vehicles would have shown that Almihdhar and Alhazmi had been living at a series of addresses in and around San Diego.
And a check with credit card companies would have shown that Alhazmi used a Visa card in his name on the Internet to purchase a ticket on Flight 77 for Sept. 11. He bought the ticket Aug. 27 and gave an address in Fort Lee, N.J., according to law enforcement records.
If the FBI had provided the airlines with the two men's names, then the airlines could have alerted authorities to their travel plans and prevented them from boarding. Since the attacks, airlines have been receiving watch list names and checking them against ticketed passengers.
Senior intelligence and law enforcement officials insist they acted appropriately given the scant information they had.
"Suppose [U.S. immigration] had the name before and Almihdhar had shown up at the airport to come to the United States," one official said. "They would have excluded him. They wouldn't have anything to charge him with. And it's unlikely he would have blabbed about the World Trade Center. That would not have been the spark to roll up the organization."
A law enforcement official similarly defended the FBI. He said the bureau was asked only to locate the two men and had no grounds to detain or arrest them.
"Even if we had established surveillance on them from day one in this country . . . and we had been notified in a timely manner, there was nothing to arrest these guys on when they entered the country," the official said.
Not everyone agrees. Loch Johnson, a University of Georgia professor of political science and an expert on terrorism, said the case appears to be "a double failure: a failure on behalf of the CIA not emphasizing the importance of tracking these two, and a failure on behalf of the FBI in light of other bombings."
Times staff writers Josh Meyer and Judy Pasternak in Washington, Sebastian Rotella in Paris, and researchers Lianne Hart in Houston and Janet Lundblad in Los Angeles contributed to this report.