A lot of criminal information on the 9/11 hijackers was uncovered by the Bundeskriminalamt (BKA, Germany’s version of the FBI), following a tip on October 28, 2001, to a suitcase full of papers written in Arabic. “In the six weeks following the attack, American and German investigators had established the money trail and for the most part they had defined the network and its connections to Osama bin Laden’s Al Qaeda organization.”
– Der Spiegel, Inside 9-11, Pages 165-167