In Hamburg, Jarrah had a succession of living accommodations, but he apparently never resided with his future co-conspirators. It is not clear how and when he became part of Atta's circle. He became particularly friendly with Binalshibh after meeting him at the Quds mosque in Hamburg, which Jarrah began attending regularly in late 1997. The worshippers at this mosque featured an outspoken, flamboyant Islamist named Mohammed Haydar Zammar. A well-known figure in the Muslim community (and to German and U.S. intelligence agencies by the late 1990s), Zammar had fought in Afghanistan and relished any opportunity to extol the virtues of violent jihad. Indeed, a witness has reported hearing Zammar press Binalshibh to fulfill his duty to wage jihad. Moreover, after 9/11, Zammar reportedly took credit for influencing not just Binalshibh but the rest of the Hamburg group. In 1998, Zammar encouraged them to participate in jihad and even convinced them to go to Afghanistan. Owing to Zammar's persuasion or some other source of inspiration, Atta, Binalshibh, Shehhi, and Jarrah eventually prepared themselves to translate their extremist beliefs into action. By late 1999, they were ready to abandon their student lives in Germany in favor of violent jihad. This final stage in their evolution toward embracing Islamist extremism did not entirely escape the notice of the people around them. The foursome became core members of a group of radical Muslims, often hosting sessions at their Marienstrasse apartment that involved extremely anti-American discussions. Meeting three to four times a week, the group became something of a "sect" whose members, according to one participant in the meetings, tended to deal only with each other. Atta's rent checks for the apartment provide evidence of the importance that the apartment assumed as a center for the group, as he would write on them the notation "Dar el Ansar," or "house of the followers." In addition to Atta, Binalshibh, Shehhi, and Jarrah, the group included other extremists, some of whom also would attend al Qaeda training camps and, in some instances, would help the 9/11 hijackers as they executed the plot: Said Bahaji, son of a Moroccan immigrant, was the only German citizen in the group. Educated in Morocco, Bahaji returned to Germany to study electrical engineering at the Technical University of Hamburg-Harburg. He spent five months in the German army before obtaining a medical discharge, and lived with Atta and Binalshibh at 54 Marienstrasse for eight months between November 1998 and July 1999. Described as an insecure follower with no personality and with limited knowledge of Islam, Bahaji nonetheless professed his readiness to engage in violence.

Question: "Where is Dar el Ansar?"

OPTIONS:
- no
- yes

Answer: "Hamburg"

Response: yes

Static electricity is like a teeter-totter. What happens if a teeter-totter is balanced? Correct! It does not move. What about when its not balanced? Yes, it will now begin to move. Charges move when they are not balanced. Charges can build up by friction. Maybe you rub your feet on a wool mat or carpet. Rubber soled shoes readily gain charges. The wool carpet easily gives up charges. The two items become unbalanced. One item has a positive charge. The other has a negative charge. The difference in charge is called static electricity. Just like the teeter-totter, something is going to move. Positive charges build up on the mat. Negative charges build up on you.

Question: "If two items build unbalanced charges, the difference is called what?"

OPTIONS:
- no
- yes

Answer: "Neutral charge"

Response: no

Rolfe put down the little dog he had been holding, and went out into the hall. The dog accompanied him, frisking about him in friendly fashion. Rolfe first examined the bedroom that he had seen Inspector Chippenfield enter. It was a small room, containing a double bed. It was prettily furnished in white, with white curtains, and toilet-table articles in ivory to match. A glance round the room convinced Rolfe that it was impossible for a man to secrete himself in it. The door of the wardrobe had been flung open by the inspector, and the dresses and other articles of feminine apparel it contained flung out on the floor. There was no other hiding-place possible, except beneath the bed, and the ruthless hand of the inspector had torn off the white muslin bed hangings, revealing emptiness underneath. Rolfe went out into the hall again, and entered the room next the bedroom. This apartment was apparently used as a dining-room, for it contained a large table, a few chairs, a small sideboard, a spirit-stand, a case of books and ornaments, and two small oak presses. Plainly, there was no place in it where a man could hide himself. The next room was the bathroom, which was also empty. Opposite the bathroom was a small bedroom, very barely furnished, offering no possibility of concealment. Then the passage opened into a large roomy kitchen, the full width of the rooms on both sides of the hall, and the kitchen completed the flat.

Question: "What did the small room look like?"

OPTIONS:
- no
- yes

Answer: "It was prettily furnished in white, with white curtains, and toilet-table articles in ivory to match"

Response:
yes