“Police in Minnesota had arrested [potential terrorist] Zacarias Moussaoui on August 16 [2001], 26 days before the attack. Moussaoui had come from London and had violated visa regulations for entering the country. His flight instructor had raised a red flag about him because he was interested only in practicing turns, not takeoffs or landings.” Although some FBI agents had urged immediate examination of Moussaoui’s computer and papers, others dismissed its importance. “FBI Director Robert Mueller even said that Moussaoui had ‘little if anything’ to do with the attacks. …Evidence suggests that he would have been the twentieth man. Or perhaps even the leader of a fifth team.”
– Der Spiegel, Inside 9-11, Page 194