The Convening Authority for Military Commissions, Susan Escallier, has entered into pretrial agreements with Khalid Shaikh Mohammad, Walid Muhammad Salih Mubarak Bin 'Attash, and Mustafa Ahmed Adam al Hawsawi, three of the co-accused in the 9/11 case. The specific terms and conditions of the pretrial agreements are not available to the public at this time.
The three accused, along with Ali Abdul Aziz Ali and Ramzi Bin al Shibh, were initially charged jointly and arraigned on June 5, 2008, and then were again charged jointly and arraigned a second time on May 5, 2012, in connection with their alleged roles in the September 11, 2001, attacks against the United States.
Information regarding military commissions can be found at the Office of Military Commissions website: https://www.mc.mil.