HAMBURG -- Around 7 one evening during Ramadan in 1998, the believers filed down a long corridor leading to the prayer room of the Al Muhadjirin mosque here, placing their shoes on the dark brown shelves before stepping onto a carpet the color of turquoise, a mixture of green for Islam and blue for heaven.
Among the worshipers was a small group of men who clustered around a severe, slight Egyptian named Mohamed Atta. Few words were spoken, but Atta moved with an air of command. Even then he was the "boss," as one of his fellow hijackers, Ziad Samir Jarrah, was to call him in a telephone conversation two days before the Sept. 11 attacks.
Authorities remove boxes from firm owned by a German Syrian in Fitzbek, northern Germany, as part of the continuing investigation into the Hamburg cell.
Sheik Adel, a guest speaker from Egypt, read from the Koran, reminded the men of the suffering of their brothers in Palestine and Chechnya, and led a prayer before the daily fast was broken, according to Abderrasak Labied, a 39-year-old Moroccan present that December evening. "Bismillah," the congregation answered, "In the name of Allah."
A large plastic tablecloth was spread on the floor and Atta sat down to eat dates washed down with a glass of milk. Beside him were Ramzi Binalshibh, Said Bahaji and Mounir Motassadeq, three members of what would become known as the Hamburg cell, the core group that carried out the attacks on New York and the Pentagon.
These students -- a group of seven men that included Marwan Al-Shehhi, Zakariya Essabar and Jarrah -- were beginning to coalesce behind a shared commitment to jihad, or holy war. Except for Atta, age 30 at the time, all were in their twenties. Over the next year, their common journey would accelerate dramatically under the tutelage of an al Qaeda operative in the city, Mohammed Haydar Zammar, and Atta's increasingly fierce desire to lash out at the United States.
Some of the deepest roots of the Sept. 11 attacks were embedded in this windy and prosperous city where Islamic extremism was cultivated unnoticed in radical mosques, a bookstore with a private backroom stocked with violent texts, informal study groups held at a university meeting place, and roundtable talks in apartments where young men wished death on America.
In one conversation, in November 1999, a German convert to Islam, Shahid Nickels, said to Atta, "Muslims are too weak to do anything against the U.S.A.," according to material collected by German investigators.
"No, something can be done," Atta replied. "There are ways. The U.S.A. is not omnipotent."
Based on interviews with some of the Hamburg cell's family, friends and associates, some speaking to a reporter for the first time, this account explores the Hamburg milieu that inspired and nurtured the group, and the road the cell followed during the 2 1/2 years of its existence. The story also draws on extensive interviews with U.S. and German intelligence and law enforcement officers as well as on material provided by other European and Arab intelligence agencies about the plot's genesis and trajectory.
The Sept. 11 attacks remain a crime without a complete history. The precise internal mechanics of the plot may never be unlocked. A full exploration of critical elements, such as the recruitment and roles of each of the 15 hijackers from Saudi Arabia, are unknown publicly a year later.
But in Hamburg, key participants in the attacks lived in plain sight. While the Sept. 11 plot evolved in secret, they inhabited a world that was both foreign and familiar to them, providing the strict discipline and focused hatred their plan required to develop, and the freedoms it needed to succeed.
An Ideal Recruiter
The patron of the Hamburg cell was a 300-pound auto mechanic with an inviting manner and war record that made him an ideal recruiter for jihad.
Mohammed Haydar Zammar was born in 1961 in Halab, Syria, and moved to Germany in 1971 with his father. From a religiously conservative family, he impressed acquaintances as exceptionally devout by age 12. He became a regular at Hamburg's mosques, including the Imam Ali mosque, known as the Iranian mosque, and the Al Muhadjirin mosque where many years later Atta would break his Ramadan fast.
By his late teens, Zammar had established a relationship with radical Muslims through Mamoun Darkazanli, a fellow Syrian, whom U.S. authorities have identified as an al Qaeda financier. Darkazanli is still living in Hamburg and is under investigation, but German officials say they do not have enough evidence to arrest him. He denies involvement with al Qaeda or the Sept. 11 plot.
After high school, Zammar attended a metalworking college and had a training period at Mercedes-Benz. In the mid-1980s, he lived in Saudi Arabia for several years, working as a translator for a German-Saudi joint venture construction company, then returned to Hamburg, where he was a driver for a hauling company.
In 1991, Zammar decided on a career in jihad, according to an Arab intelligence agency. He traveled to Pakistan on a German passport, then on to an Arab guesthouse in Afghanistan. Zammar underwent training in weapons, explosives and tactics with other Arab fighters. He was then assigned to a second, elite camp near Jalalabad.
Although al Qaeda's leader, Osama bin Laden, was living in Sudan at the time, the organization had established training camps in the eastern part of Afghanistan under the protection of the warlord Gulbuddin Hekmatyar. Zammar fought alongside Hekmatyar's troops against the communist Afghan regime.
Battle-hardened, Zammar returned to Hamburg at the end of 1991, and over the next few years visited Syria, Jordan, Turkey and Sweden while working as a mechanic and at odd jobs in Germany. In 1995 he went to fight in Bosnia, where he was based in Zenica with other Arab mujaheddin.
In 1996, Zammar set off for another visit to Afghanistan, where he formally pledged allegiance to al Qaeda, according to an Arab intelligence agency. The next year, the Germans, tipped off by Turkish intelligence, placed Zammar under surveillance. But, as with a later surveillance of one of Atta's roommates, Said Bahaji, the tail was dropped within months for lack of evidence of criminal planning.
"What we did not see were concrete signs for such a violent act as occurred in New York," said Peter Frisch, the former head of the German Office for the Protection of the Constitution, which monitored extremists in the country. "We had neither the people to do [surveillance], nor did we know that we should."
Hamburg -- and Germany as a whole -- was an almost risk-free environment for Islamic radicals. German officials, mindful of the country's Nazi past, say now that they were reluctant to target mosques and risk allegations of racism or religious persecution. Such reservations meant that while authorities were aware of the calls to arms that fired up the members of the Hamburg cell, they saw no cause to intervene.