Mohammed bin Nasser Belfas
1999: Mohamed Atta is regularly attending Islamic study group meetings led by a fellow Hamburg student named Mohammed bin Nasser Belfas.
October/November 2000: Mohammed Belfas, mentor of lead hijacker Mohamed Atta and Agus Budiman travel to the US.
Belfas, who led an Islamic study group that Atta attended in Hamburg and also worked in a computer warehouse with Atta, bin al-Shibh, and Marwan Alshehhi, obtains an ID card in the same fraudulent way as the 9/11 hijackers later will.
During this period, they meet with Abdurahman Alamoudi, a prominent Muslim activist whom the US has linked to Osama bin Laden. Belfas will later say the purpose behind their meetings with Alamoudi was to request some favors.