In 1996, he disappeared for a full two years. When he returned to Hamburg, he wore the full beard and long tunic of an orthodox Muslim. He founded an Islamic student group and petitioned the university for a meeting room and funds for study materials.
No one thought much of it. Atta had always been religious, and these informal sabbaticals were common among German graduate students.
Eventually, seven years after he started, Atta won his graduate degree in urban planning. His thesis described the conflict between modernity and Islam as it played out on the streets of Aleppo, an old stone city on the desert plateau of northern Syria.
When he was awarded his degree in August 1999, he declined to shake hands with the women on his review committee. It would have offended his strict religious beliefs.
Volker Hauth, an architect and friend, accompanied the somber Atta on his researches in Aleppo. It has been five years since the two spent time together, and Hauth has trouble reconciling the man he knew with the Atta who is suspected of helping orchestrate the terrorist attacks on New York and the Pentagon. Yet Hauth says that even then there were hints of what Atta would become: an Ueberzeugungstaeter, a German word that translates as "religious criminal."
"I knew Mohamed as a guy searching for justice," Hauth said. "He felt offended by this broad wrong direction the world was taking."
A year later, Atta disappeared from Hamburg for good. Once again, no one knew where he was headed.
Atta, then 31, and a Hamburg roommate, Marwan Al-Shehhi, 21, flew into the United States within days of each other in mid-2000. They headed out across the southern United States on an unusual, extended shopping trip, looking for a place that would teach them to fly American airliners.
They made stops in Oklahoma and possibly Texas before settling on Huffman Aviation in Venice, Fla., where they arrived eager as puppies. They said they were Afghan cousins who had come to America from Germany.
Atta's old-fashioned beard was long gone. So was the robe. He and Al-Shehhi wore uniforms of modern, casual America: pressed khakis and polo shirts. When they moved into a little pink house in nearby Nokomis, they brought cookies to their rental agent.
Plotting to fly airplanes into the sides of skyscrapers filled with people seems a very long way from calculating the ideal traffic volumes and street setbacks to keep an ancient Arab souk alive. But architecture and its academic cousin, planning, embrace a wide range of disciplines in the end all aimed at one thing: Making the world suit your vision of it.
This can involve building things. It can also mean removing them.
Investigators and the media have talked much since the Sept. 11 attacks about the four "terrorist cells" that launched them and the supposed logistical complexities that had to be overcome.
The known information regarding the suspected hijackers, however, doesn't offer much evidence of complexity. Their long-term preparations appear to have occurred mainly in two places, Florida and San Diego. The cells in each of these places appear to have been quite small--two, sometimes three people.
The men on each coast kept to themselves and stayed below the horizon of public scrutiny. The men suspected of killing as many as 6,900 people lived on the quiet fringes of urban America without incident, in seedy rooms where landlords asked for the rent, not references. Their only known encounter with law enforcement was a single traffic ticket for driving without a license.
In the end, the original small groups were augmented by at least a dozen more terrorists, about whom very little information has emerged. The men who swelled the total number of hijackers to 19 might have been needed for little more than muscle, to help with the physical task of taking over the aircraft.
Little is known for certain about any of the hijackers. Even now, more than two weeks after they died such very public deaths, no one can be certain even of their names.
Within 72 hours of the attacks, the FBI released a list of the 19 suspected hijackers. Six of those names appear to be aliases. There is a chance even more of them are wrong. The confusion over the names complicates efforts to learn who the hijackers were and what motivated them.
What follows is a description of what is known about their lives and, especially, their movements in the final months.
The core handful of suspects was highly mobile, traveling from the United States to Asia, Europe and Africa and back again. Almost all of what they did on these trips is unknown, although authorities report meetings with other suspected terrorists--on the beach in Barcelona, at an airport in Malaysia.
The conspirators did little to attract notice. They changed residences often. They listened to sermons at local mosques. Mainly, they took their flying lessons and waited.
Atta and Al-Shehhi set up housekeeping in Florida last fall. Men using the names Nawaf Alhamzi and Khalid Al-Midhar--occasionally joined by a man who went by Hani Hanjour--did the same in San Diego.
The two locales have much in common. California and Florida are one-two in the nation in pilot training. Flight schools are so numerous in Florida that the state calls itself the "aviation state."
Both places have diverse, fast-changing populations, where almost anyone can blend in. San Diego, in particular, had a vibrant Muslim community that welcomed Al-Midhar and Alhamzi.
Alhamzi told people he was a native of Saudi Arabia, in San Diego to study, although he never told friends what or where. In 1999, Alhamzi rented a unit at the Parkwood Apartments, a well-kept building in a middle-class suburban neighborhood.
Alhamzi later shared his small place with another Middle Eastern man, according to manager Holly Ratchford. Al-Midhar listed the same address the following spring.
Alhamzi was about 5 feet, 4 inches, and thin, Ratchford said. She described him as a polite man who paid his rent on time and never caused trouble. "He didn't stick out," Ratchford said. Alhamzi's English was sketchy, but he was outgoing. In the mornings, he often stopped by the rental office and said hello to the managers. He drank coffee and ate cookies with them.
Al-Midhar was a less constant presence. He came and went. Ratchford never even learned his name. Investigators now say one of the places Al-Midhar went was Malaysia, where in January 2000 he met with an operative of Osama bin Laden, the accused terrorist leader.
In May of that year, Al-Midhar and Alhamzi showed up at a San Diego flying club owned by Fereidoun "Fred" Sorbi.
"The first day they came in here, they said they want to fly Boeings," recalled Sorbi, 52. "We said you have to start slower. You can't just jump right into Boeings."
Sorbi said he gave them introductory lessons in a Cessna or Piper. Each man took an hour at the controls. One of the men, Sorbi can't remember which, prayed loudly as his friend approached landing.
Alhamzi regularly went to the local Islamic Center, where he met Abdussattar Shaikh, a retired San Diego State University English professor and member of the local police commission. Perched on a bluff overlooking a valley in east San Diego County, Shaikh's large two-story house has been a gathering spot for Middle Eastern men for two decades. The meetings aroused more curiosity than suspicion in the sleepy Lemon Grove neighborhood.
Shaikh rented Alhamzi a room. Except for Al-Midhar, Alhamzi appeared to have no friends at all. Shaikh describes Alhamzi as a homebody who read books on Islam and visited Arabic Internet sites. He followed a strict Muslim diet.
"While he lived with me, I never saw him use a telephone. I wondered if he had any family at all," Shaikh said. "He said he came here to learn English, but I didn't see him going to school very often. He told me he was taking English classes at a downtown language school."
Alhamzi said he had applied for an extension on his student visa. He told Shaikh he eventually wanted to become a pilot and take a Mexican bride.
"So I taught him a few Spanish phrases, like que pasa," Shaikh said.
Alhamzi even posted a message on a lonely hearts Web site: "Saudi businessman looking for a bride who would like to live in this country and Saudi Arabia." Shaikh said there were only two responses, both from Egyptian women.
"He told me once that his father had tried to kill him when he was a child. He never told me why, but he had a long knife scar on his forearm," Shaikh said.
Al-Midhar shared Alhamzi's room at the house for about a month, apparently leaving sometime in October 2000.
"When Khalid left, he told me he was returning to Saudi Arabia, where he had a wife and children. After he left, I never heard from him again," Shaikh said.
Alhamzi left in December 2000. He said he was going to San Jose for school. In January, he called Shaikh, saying he was in Arizona.
"That's the last time I heard from him," Shaikh said.
At Huffman Aviation in Florida, Mohamed Atta identified himself as Amanulla Atta Mohammed. His Hamburg friend, Marwan Al-Shehhi, called himself simply Marwan. They paid Rudi Dekkers, the flight school's owner, $10,000 each for four months' training. They earned certification to fly single-engine aircraft. That qualified them to train for jets.
Dekkers said Atta was aloof, a loner. The "chubby" Marwan, wearing casual button-downs with shirttails flying and sneakers, was more "likable," he said.
Atta used computers at the public library and worked out at a Delray Beach health club.
"He just seemed like a businessman," said Brad Warrick of Pompano Beach, who rented cars to Atta three times. "He spoke English very well. It seemed like he had been in the country for some time. He was just your everyday, local guy."
Atta grew up in Cairo. His father was a lawyer. Two sisters became university professors. Atta studied architecture as an undergraduate, then left in 1992 for graduate school in urban planning at the Technical University in Hamburg. He specialized in the development of old Islamic cities.
Ralph Bodestein, a German citizen now living and working in Beirut, said he and Atta worked together in 1995 studying traffic patterns in a historic part of Cairo.
"He was a very engaged urban planner," Bodestein said. "The Mohamed I know was not a terrorist. But the photo they show in the press, that is the person, that is the same person I knew.
"He was a very complex person. On the one hand, he was a very religious person. He was growing a beard, he had just come back from a small hajj [a religious pilgrimage]. He did pray five times a day. . . . On the other hand, he was very full of idealism and he was a humanist. He was very much interested in social work.
"The person I knew then is not a person who could do what he is said to do now. There must have been quite a development."
Volker Hauth, Atta's architect friend, said Atta's faith was central to his life.
"The religious convictions of both of us--his Islamic and mine Protestant--were a kind of bonding for us," Hauth said. "In Germany at that time, there were a lot of students from East Germany with no religion, and this was something difficult for Mohamed."
From the onset of their friendship, Atta was troubled by what he saw as social injustice and the inequitable distribution of wealth in the world, Hauth said.
"We didn't speak much about America but about intercultural conflicts in Egypt, where the Western and Islamic worlds come together," said the architect, who shared his friend's views that a gulf was widening between the world's haves and have-nots.
"He didn't believe in fighting injustice with injustice, at least when I knew him," Hauth said. "I don't want to excuse what happened--it cannot be excused. It wasn't justice. But I can see where he might have seen it that way in a cynical moment."
German investigators say Atta for a time shared his Hamburg apartment with Al-Shehhi, who was in his first year at Technical University. He was 10 years younger than Atta and a native of the United Arab Emirates.
With his goatee, receding hairline and wire-rimmed glasses, Al-Shehhi looked innocently bookish. People found him friendly. When he and Atta traveled in the United States, because of their easy camaraderie, people frequently mistook them for cousins.
A third suspected hijacker, a man who used the name Ziad Jarrah, was also a student in Hamburg. He too was seen frequently with Atta. Jarrah is the only one of the suspects known to have actually been a competent pilot. He held a commercial pilot's license, records show, and studied flight engineering at the University of Hamburg. He was one of two children from a Sunni Muslim family in the Bekaa Valley of Lebanon. His family is affluent. They say he could not have had anything to do with the hijackings.
"Ziad is not involved in this terrible act," said an uncle, Jamal Jarrah. "He has everything going for him. He attended Christian school and was always a good student. And he's a good student at the university. He had one more year to study. Then he was planning to return to Lebanon and marry his girlfriend. He was in a position to have a very decent life.
"He is not a radical. He is not affiliated in any religious or political groups. He's a normal Muslim like others, but not zealous about it."
Jarrah called home weekly, the uncle said. In the last call, before the attacks, he talked excitedly about his father's new car. He planned to bring his Turkish girlfriend home for a wedding next summer. He went to the U.S. for flight training, the family said.
Atta's father says he believes many of the suspects in the hijackings have been framed. The father, Mohammed Al-Amir Awad Al-Sayed Atta, has seen the airport videotape purporting to show two of the suspected hijackers before the attack. The father said one of the men appears to be his son but that the tape must have been doctored. He insisted he had talked to his son by telephone since the hijackings.
"Neither me nor my son has been involved in any political party. We are people who keep to ourselves. We don't mix a lot with people. We are all successful," he said. "Even the security officials were polite when they asked questions about Mohamed, which is not really their habit, because they knew we are good people."
For someone suspected of steering a jetliner into the Pentagon, the 29-year-old man who used the name Hani Hanjour sure convinced a lot of people he barely knew how to fly.
Hanjour attended CRM Airline Training Center in Scottsdale, Ariz. Duncan Hastie, the owner of CRM, said Hanjour attended the school the last three months of 1996. Then Hanjour "sort of disappeared," he said, returning in December 1997.
Hastie said Hanjour wasn't much of a pilot.
"One of the first accomplishments of someone in flight school is to fly a plane without an instructor," Hastie said. "It is a confidence-building procedure. He managed to do that. That is like being able to pull a car out and drive down the street. It is not driving on the freeway."
Hastie said that three months normally would be enough to earn a private pilot's certificate, but Hanjour "did not accomplish that at my school."
Hastie said Hanjour was 5 feet, 5 inches, and thin, about 120 pounds. Hastie described him as intelligent, friendly and "very courteous, very formal."
After Hanjour last took classes at the school, he called back numerous times to ask about further instruction. At least once, Hastie recalled, Hanjour said he was living in Florida. He told Hastie he had continued with his training.
"He was a pain in the rear," Hastie said. "We didn't want him back at our school because he was not serious about becoming a good pilot."
In May 2000, a man calling himself Hani showed up with Alhamzi at Sorbi's flying club in San Diego.
Across the country in Florida, in December, Atta and Al-Shehhi visited Simcenter Inc. in Opa-Locka, outside Miami, for lessons on a Boeing 727 flight simulator. They paid $1,500 in cash for six hours of lessons--three hours apiece.
Atta and Al-Shehhi, by then, had each logged about 300 hours of flight time in small aircraft, said Simcenter owner Henry George. The two were clearly amateurs, he said, but knew enough to maneuver a commercial jet in the air.
"They said they were pursuing a career with a big commercial carrier in Egypt," George said. Inside the simulator, "they did the takeoff. And then when we were 'in the sky,' they maneuvered around. They did the whole thing."
The two men knew enough, George said, to steer an airplane into a building.
Just after New Year's Day 2001, Atta hopped a flight from Miami to Madrid. Whether he stayed there or caught another plane is unknown. About the same time, Al-Shehhi went to Casablanca, Morocco.
At Miami International Airport, Atta was allowed back in the country despite having overstayed his visa by 32 days on his previous visit. Al-Shehhi also returned without incident, despite having overstayed his previous visa by about five weeks.
Their whereabouts for the next several months are unknown, but by mid-spring they were back in Florida. On April 26, at the wheel of a red 1986 Pontiac, Atta was pulled over on a routine traffic stop in Broward County, north of Miami, and cited for driving without a license. He gave a Coral Springs address.
They drifted to another oceanfront Florida town, Hollywood, between Miami and Fort Lauderdale. They rented an apartment on Jackson Street for a month in mid-May. Atta paid $650 upfront for low-rent rooms with worn, kitschy furniture. He told neighbors he was there to take flight lessons. He and Al-Shehhi moved around in the red Pontiac, which one resident says was plastered with Arabiclanguage stickers.
The Hollywood apartment catered to transients. The suspected hijackers fit in among the day laborers, migrant workers and students who came and went at all hours, spoke a Babel of languages and paid for almost everything with cash.
After Atta received the traffic ticket, Al-Shehhi applied for and received a Florida driver's license, listing a Mailboxes Etc. address. Al-Shehhi made a second overseas trip, this time from Miami to Amsterdam. He stayed two weeks and returned about the same time that two more of the suspected hijackers made their first appearances in Florida.
Jarrah, the Hamburg engineering student, rented an apartment together with Ahmed Alhaznawi in Lauderdale-by-the-Sea, just north of Fort Lauderdale. On May 6, a man identifying himself as Jarrah walked into a gym off Federal Highway in Dania, Fla. He wore reading glasses and carried a backpack. He wanted to learn self-defense.
Jarrah bought a two-month membership, listing his residence as 1816 Harding St. in Hollywood. When he extended his gym membership for an additional two months, he said he planned to go "back to Deutschland." For $1,000 in cash, gym owner Burt Rodriguez gave Jarrah special one-on-one instruction in self-defense. He found his student, who stood about 5 feet, 10 inches, and weighed 175 pounds, as strong and fit as a soldier.
"We spent a lot of time talking," Rodriguez said. "Some times we spent time talking about Buddhism, about the art of blending. And he was very receptive."
Rodriguez attempted to take the measure of Jarrah, as he does with all his students. He came away believing the man in the T-shirt, quick with a smile, lacked the toughness to win in close-quarter combat.
In summer, everyone was on the move.
On June 12, Al-Shehhi moved into a gated community in Delray Beach called the Hamlet Country Club. Resident Nancy Adams, 34, a paralegal, believes Atta came along too. The parking places for their cars--the red Pontiac and a Toyota--were next to hers, she said.
"They told me they were here on business computer work," she said. They also wanted to know the local hot spots. She directed them to Boston's on the Beach, 32 East, Luna Rosa's and City Limits.
On his rental application, Al-Shehhi, when asked his permanent residence, wrote: "NONE. I'm wandering."
In late June, Atta went to Las Vegas, where he met with two of the San Diego crew: Alhamzi and Hanjour. The timing suggests the meeting could have been a strategy session for the hijackings.
Around this time, Atta, Al-Shehhi and the three from California--Al-Midhar, Alhamzi and Hanjour--made brief, separate trips abroad.
Al-Midhar and Alhamzi returned shortly before they were placed on an immigration watch list, which would have barred their reentry into this country. They were later flagged as suspected terrorists because the CIA had discovered that Al-Midhar had met with a Bin Laden operative in Malaysia last year.
Preparations for the hijackings were underway.
A number of other men using names that later turned up on the FBI's list of 19 suspected hijackers began showing up in Florida. They rented modest rooms, stayed a week or a month and moved on to similar places in similar towns. Two moved into the Bimini Hotel in Hollywood. "They were nice kids," owner Joanne Solic said. "Clean-cut, nice looking and courteous. Lots of hellos and thank yous."
In late summer, the Californians--Al-Midhar, Alhamzi and Hanjour--went to Maryland, the staging area for the flight from Dulles International Airport that crashed into the Pentagon.
Hanjour, always an uncertain pilot, showed up at flight school in Bowie, Md. Three times, he attempted to rent a plane. Each time, a different instructor took him on a test flight and deemed him incompetent to fly alone.
"We have a level of standards that we hold all our pilots to, and he couldn't meet it," said the manager of the flight school.
Hanjour could not handle basic air maneuvers, the manager said. Hanjour was also reluctant to provide his address, a standard part of the plane rental application.
Hanjour, Al-Midhar and Alhamzi joined two other suspects at the Motel Valencia, on the outskirts of Laurel, Md. Gail North, a resident housekeeper, said two of the group checked into a room in the hotel's modern wing and would open the door only a crack to pass out dirty towels and receive clean ones.
By Sept. 2, all five had moved into the seediest of the Valencia's buildings, behind the unpainted wooden door of Room 343. For a weekly rate of $280 plus tax, they had a kitchenette, a tiny living area and one bedroom.
Their pressed khakis and button-down shirts made them stand out from other tenants, a crew mostly down on its luck.
In the days before the attacks, the suspected hijackers separately purchased tickets for their target flights. Many bought first-class and business-class seats.
The group that had been in San Diego worked out regularly at a nearby Gold's Gym. Making conversation, a gym employee asked the meanings of their names. Hanjour said his given name, Hani, meant warrior.
On Sept. 7, about 10:30 a.m., all five left the Valencia for good. That same night, down the coast in Florida, Atta and Al-Shehhi went to Shuckums sports bar in Hollywood, along with a still unidentified third man. The owner, Tony Amos, says Atta sat quietly by himself and drank cranberry juice and played a video game, while Al-Shehhi and the other customer tossed back mixed drinks and argued.
Al-Shehhi sent his food back to the kitchen, Amos said, then complained about the bill. Barmaid Patricia Idrissi said the men seemed to have gotten the impression she took them for deadbeats. She recalls Atta barking at her: "I am an American Airlines pilot. I can pay my bill," and pulling out a thick wad of fifties and hundreds. He peeled off $50 to pay the $48 tab.
The separate groups stayed together over the last days, in Maryland and Florida. The San Diego crew stayed intact right onto their aircraft. The three German students, Jarrah, Al-Shehhi and Atta, split up at the end, each aimed at a different plane. They are believed to have piloted three of the four hijacked jets. After spending months together in flight schools and apartments, Atta and Al-Shehhi appear to have parted company around Labor Day, when Al-Shehhi led a cohort of three men into Deerfield Beach, a placid, middle-class community by the Atlantic just south of Boca Raton.
Al-Shehhi drove the three to and from the Crystal Cay Motel, where they had an upstairs corner room. Rooms at the pale yellow, two-story building with a faded white shingle roof rent for about $45 a night.
A few doors down from the suspected hijackers, James Smith sat on the balcony of his efficiency, enjoyed the cool night breeze and watched. Nearly every day, Al-Shehhi would come by in a car to pick up the three men. Sometimes he drove a red car, sometimes a black one. Once, he brought the three back from grocery shopping and Smith stole a peek at a box of Kellogg's Frosted Flakes.
Despite having a telephone in their room, the men regularly used a pay phone in front of the motel. Al-Shehhi stayed a few blocks north, at the Panther Motel, along with yet more men. They spent their days out, evenings closeted in the room.
Al-Shehhi checked out of the Panther on Sunday, Sept. 9. By Tuesday morning, the German students and their accomplices had made their way north to Boston and Newark, N.J.
After they left, owner Richard Surma, cleaning out the rooms at the Panther, found a tote bag in the trash. It was packed with aeronautical maps, a protractor and Boeing 757 flight manuals.
On Sept. 11, the man using the name Mohamed Atta boarded American Airlines Flight 11, out of Boston for Los Angeles, with men using the names Waleed M. Alshehri, Wail Alshehri, Satam Al Suqami and Abdulaziz Alomari.
The man using the name Marwan Al-Shehhi boarded United Airlines Flight 175, also bound from Boston to Los Angeles, with men using the names Fayez Ahmed, Ahmed Alghamdi, Hamza Alghamdi and Mohald Alshehri.
The man using the name Ziad Jarrah boarded United Flight 93, headed from Newark to San Francisco, along with men using the names Saeed Alghamdi, Ahmed Alnami and Ahmed Alhaznawi.
The man using the name Khalid Al-Midhar boarded American Flight 77, out of Dulles for Los Angeles, with men using the names Majed Moqed, Nawaf Alhamzi, Salem Alhamzi and Hani Hanjour.
On Sept. 11, the planes carrying the men using these names crashed, in order, into the north tower of the World Trade Center, the south tower of the World Trade Center, a field in Stony Creek Township, Pa., and the Pentagon. All aboard died, including the men using these names and a great many other men, women and children, aboard and elsewhere, all using their own names for the very last time.
The article was written by Times staff writer Terry McDermott, based on reporting by Carol J. Williams in Germany; Michael Slackman in Lebanon; Ranwa Yehia in Egypt; Kurt Streeter in Arizona; H.G. Reza, Matt Lait and Scott Glover in San Diego; Greg Krikorian, Robert J. Lopez, Rich Connell, Henry Weinstein, Richard O'Reilly and Patrick McDonnell in Los Angeles; John-Thor Dahlberg, Evan Halper and Mark Fineman in Florida; and Lisa Getter, Judy Pasternak and Bob Drogin in Washington.