The following documents have been declassified by the CIA pertaining to the 9/11 attacks.
Central Intelligence Agency (CIA) Inspector General Report on 9/11/01
Joint Response to Draft IG 9/11 Report [15 Pages, 1.05MB]
Response to Inspector General’s 9/11 Accountability Final Draft Report [10 Pages, 0.8MB]
OIG Report on Counterterrorism Detention and Interrogation Activities, 07 May 2004 [159 Pages, 8.83MB] – This report came in response to my FOIA request to the CIA regarding the treatment of Khalid Sheikh Mohammed while at Guantanamo Bay.