Pretrial hearings were held on Monday at Guantanamo Bay in Cuba for the self-proclaimed September 11th mastermind Khalid Shaikh Mohammed and his four alleged co-conspirators.
The men appeared in military court at the U.S. Naval Base in Guantanamo Bay, Cuba for four days of hearings.
Mohammed was sporting a red-dyed beard and military-style fatigue jacket and another couple defendants were wearing camouflage vests.
All five defendants acknowledged to their judge they understood their right to skip the rest of the week's hearings.
Some of the victims' families were in Cuba for the proceedings.
Observers viewed a video feed of the proceedings from behind soundproof glass, with a 40-second audio delay so that authorities could mute any classified information.
The sound and video was completely shut off at one point Monday by a person outside the courtroom Monday during discussion of so-called CIA black sites, or overseas prisons where the defendants were held.
"There does seem to be a little kick in the back of the machine that was made to be operated by someone who was not in the courtroom," said Benjamin Davis of the University of Toledo College of Law. "It didn't seem to be the court security officer and quite honestly no one really seemed to know who had decided to press that button."
The defense says their clients were tortured in "black sites," and Mohammed was waterboarded 183 times.
The judge has ruled the details of their interrogations must be kept secret.
The government is expected to argue it has the right to monitor communications between the defendants and their attorneys.
Davis said the government should err on the side of more information.
"I think, for the purposes of this hearing, it'd be much better if it was all out in the open," Davis said.
The men were arraigned in May but the trial is likely to be at least a year away.
If convicted, all five men will face the death penalty.
NY1's Bobby Cuza is in Guantanamo Bay and will have reports from the hearing throughout the week.