American Airlines Flight 11 was in line for takeoff from Logan International Airport, the passengers already reminded to turn off personal electronic devices, when Mohamed Atta, in Seat 8D in first class, dialed his cell phone for the last time.
The call rang aboard another sparsely occupied jetliner a bit farther back on the same tarmac, on a cell phone belonging to Marwan al-Shehhi, in Seat 6C on United Airlines Flight 175.
The conversation between the two men, so close that they called each other cousin, lasted less than one minute — just long enough, investigators say, to signal that the plot was on.
That simple communication was the culmination of months of meticulous planning and coordination that by 10 o'clock on the morning of Sept. 11 would become the worst terrorist attack in U.S. history.
With all the suspects dead and no evidence, as yet, from any accomplices, investigators have been left to re-create the architecture and orchestration of the plot largely from the recorded minutiae of the hijackers' brief American lives: their cell phone calls, credit card charges, Internet communications and ATM withdrawals.
What has emerged, nearly two months into the investigation, is a picture in which the roles of the 19 hijackers are so well defined as to be almost corporate in their organization and coordination.
Investigators now divide the 19 into three distinct groups:
Atta, considered the mastermind, and three other leaders who chose the dates for the attack and flew the planes; a support staff of three who carried out the logistics of renting apartments, securing drivers' licenses and distributing cash to the teams that would take the four planes; and beneath them, 12 soldiers, or "muscle," whose sole responsibility seems to have been restraining the flight attendants and passengers while the leaders took over the jets' controls.
The leaders had researched their plans so well that they knew just when each of the four cross-country flights would reach its cruising altitude — the moment, investigators say, when the hijackers stormed the cockpits to confront the pilots with box cutters. The coordination was so thorough that each of the four hijacking teams had its own ATM card, and they all used a single PIN. The slightest misstep could trigger intense frustration: More than once last summer in Florida, when money transfers from abroad had not arrived on the expected dates, security cameras captured several hijackers glaring impatiently into ATM screens.
The hijackers made a true technophile's use of the Internet, online chat rooms and e-mail. But when it came to their most crucial communications, they did what an al-Qaida manual on terrorist operations instructs: They met in person. They chose as their meeting place the same locale where generations of American conventioneers have met to exchange information about their crafts: Las Vegas, where investigators now say they believe the most crucial planning for Sept. 11 occurred.
But unlike traditional conventioneers who cluster in casino hotels that replicate the Pyramids or the New York City skyline, the leaders and their logistics men stayed at the seediest end of the famous Las Vegas Strip, next to the "Home of the $5 Lap Dance," at a cheap motel guaranteed not to have surveillance cameras. They stayed briefly, only as long as it took to exchange important information and apparently did not visit the casinos or any of the other purveyors of easy vice in America's City of Sin.
Many of the 19 hijackers, perhaps all of them, spent time in Osama bin Laden's Afghan training camps, investigators now say. Some of the Sept. 11 soldiers appear to have met there. And like Atta and the other pilots, the muscle did not seem to fit the profile of suicide bombers as desperate and impoverished young men. With the exception of one, they were
all Saudis, relatively well off and well educated. Yet while the leaders seemed to be Islamic zealots, the muscle did not, indulging often in pornography and liquor.
There is still much that investigators do not know. While they believe, for instance, that the plot cost nearly $500,000, they have been able to trace only half of it back to a suspected al-Qaida source. They know where the leaders met but not what information they exchanged — among hundreds of e-mails seized from computers in Florida and Las Vegas, there is no "smoking gun" or description of the Sept. 11 attacks, a senior investigator said.
The investigators say they are unsure how the soldiers were recruited. And they do not know how those men thought the story was going to end, if they knew they had signed on to die.
"This went totally by the book," one senior government official said. "It has all the earmarks of al-Qaida. It was well organized, far from a half-baked operation. They had good coordination, excellent communication that is hard to track, and a good, simple plan. Somebody did their homework."
Investigators say their best theory is that Sept. 11 was a franchise operation and the leaders closely hewed to the dictates of the al-Qaida terror manual.
The plot was first pieced together, they believe, at least two years ago, in Hamburg, Germany, where three of the men who would later be leaders and pilots — Atta, Shehhi and Ziad Amir Jarrah — were living as students. Senior law enforcement officials say those three men then received the blessing — and, crucially, cash — from al-Qaida, although investigators say they do not know who in Osama bin Laden's organization approved the operation. Several officials say they suspect it was bin Laden himself.
"They met with somebody else who was calling the shots" in Germany, one official said. "But we don't know who that person is."
Shehhi and Atta received visas to enter the United States in January 2000, and Jarrah arrived in June of that year. Another pilot, Hani Hanjour, had been living in Southern California since 1996, and two of the logistics men, Nawaf Alhazmi and Khalid Almihdhar, had moved to San Diego in 1999.
Investigators do not know for certain how the Hamburg and California groups came together. But evidence suggests it was through al-Qaida channels. Almihdhar had been captured on a secret videotape at a meeting of suspected bin Laden operatives in Kuala Lumpur, Malaysia, in January 2000.
The money for the operation began arriving in bank accounts in the United States, at SunTrust Bank and Century Bank in Florida, in the summer of 2000. Atta received slightly more than $100,000, Shehhi just less than that amount. About half of the $500,000 used to pay for the operation, senior FBI officials believe, was sent in wire transfers from banks in the United Arab Emirates and much of the rest from Germany, but one official said the authorities suspect it originated in Pakistan.
Travel records show each of the men making several trips in and out of the United States in 2000 and early 2001 — to Prague, Czech Republic; Bangkok, Thailand; Spain and Saudi Arabia. Atta took seven international trips; Shehhi took five. In this country, they all had begun taking flying lessons, in Phoenix, San Diego and South Florida.
By spring 2001, the 12 men whom investigators call the muscle had begun to arrive from Saudi Arabia. The Saudi government, stung by American reports that most of the hijackers received visas from their country, initially said the hijackers used fake identities stolen from innocent citizens. But the FBI says that it has confirmed the identities of all 19 of the hijackers and that 15 were Saudis.
While the Saudi government has restricted the FBI and reporters from interviewing the families of the men, the families of the group the FBI labels the muscle have told Arab newspapers that their sons left within the past 18 months, variously saying they were going to seek religious counseling, on pilgrimage or on jihad in Chechnya. An investigator said there was evidence that the muscle spent at least a year in al-Qaida training camps.
The family of one, Mohand Alshehri, said he had studied at Imam Muhammed Ibn Saud Islamic University in Abha, Saudi Arabia, for one semester. The father of two others, Wail and Waleed Alshahri, said his sons had studied to become teachers. Another, Ahmed Alnami, had studied law in Abha. And the man the FBI identifies as the third logistics man, Majed Moqed, studied at King Saud University in Riyadh, Saudi Arabia, in the faculty of administration and economics, according to Arab newspapers.
Most hailed from poor villages where fundamentalism thrives. But their families appeared to be on the upper rungs; their fathers were religious leaders, school principals, shopkeepers and businessmen.
None had visited the United States before, and several appeared to speak little or no English. Once they arrived, the logistics men helped them fade into the hum of American life. Hani Hanjour helped some rent an apartment in Paterson, N.J. Others cycled through one apartment in Delray Beach, Fla. Almihdhar helped some obtain illegal driver's licenses and photo identifications in Virginia.
The leaders and logistics men seemed to "buddy up" with their junior partners. One muscle member had an ulcerated leg, and a pilot-leader took him to a hospital in Palm Beach County, Fla. At first, Atta and Shehhi lived together in Florida; Al-Shehhi then moved in with Fayez Rashid Ahmed Hassan al-Qadi Banihammad, and Atta with Abdulaziz Alomari, the last hijacker to arrive.
Most of the 19 obtained Social Security numbers, which allowed them to open bank accounts and obtain credit cards. They seemed, the FBI says, to remain self-contained, with little or no help from a support network in the United States. Investigators suspect the help came from money men in the United Arab Emirates and several key lieutenants in Germany and Afghanistan.