Mohammed will be joined by four co-defendants in pretrial proceedings as a new judge presides over the military commission nearly 20 years after 2,977 people were killed at the World Trade Center, Pentagon and Shanksville, Pennsylvania.
The moment is primed to create headlines as the legal process resumes not only days before the 20th anniversary of the attacks, but also less than two weeks after the U.S. military completed its chaotic withdrawal from Afghanistan.
It is also fraught with a sense of justice delayed for years, charged battles over whether civilian or military authorities should try the cases and of course, the fight over the infamous Guantanamo Bay complex itself, where a number of those swept up in the war on terror were held indefinitely.
Also at issue is how much the public will learn and when. With concerns about classified information, images and transcripts from the courtroom, while in public view, will be tightly controlled and the proceedings could be halted for national security reasons. After this pretrial phase Sept. 7-17, another pretrial continuation is set for Nov. 1-19.
There could be additional pretrial phases added after that, at the discretion of the judge. After that, the military commission will go through a process that could last two months to select military officers to serve as panel members. The trial itself could begin as soon as next April, although a date is not yet definite. Mohammed and his codefendants face capital charges that could carry the death penalty if convicted.
Approximately 15 reporters received a tour Sunday afternoon of the Expeditionary Legal Complex (ELC) at Camp Justice, where the hearings will take place.
Here's what we learned about the courtroom and proceedings, and how we got to this point:
A nearly decade-long detention
The defendants in this case were arraigned in 2012, but have yet to truly see their day in court because of a numerous delays in the pretrial process.
One of the key issues to be decided before the trial can begin is what evidence will be admissible. The defendants were held in secret prisons abroad, called CIA black sites, before they were transferred to the Guantanamo facility. There, they were subjected to enhanced interrogation techniques, which many human rights organizations and the defense teams argue are tantamount to torture.
Accounts obtained after the prisoners came to Guantanamo are also in question. Defense lawyers contend that their clients were already conditioned to give their interrogators the answers they wanted to hear.
The court itself has also undergone many changes during the duration of the trial. Established by former President George W. Bush in 2001, the Guantanamo military commission was revised via Congressional act in 2006 and later amended through the legislative branch again in 2009. Former President Obama attempted to transfer detainees to the U.S., but was effectively blocked by Congress.
Critics have argued the military court is unconstitutional and unjust because the accused are denied the right to due process and a speedy trial.
There is a sound-proof gallery where 53 reporters and family members of 9/11 victims and survivors of the terrorist attacks can watch the proceedings through sound-proof glass. A blue curtain separates family members of victims or 9/11 survivors from the press, if they wish to pull it closed for privacy. The proceedings can also be observed by members of the public at Fort Meade, Maryland via closed-circuit TV.
If classified material is raised during the trial, the judge or trial judiciary staff, such as a court information security officer, or CISO, could stop the closed-circuit feed - cutting off the presentation before any classified information is revealed publicly. The prosecution could also preemptively invoke national security to disrupt the defense's argument even before any classified information is actually revealed.
The courtroom - built specifically for the trial of the 9/11 defendants, cost $12 million to construct in 2008 and is basically a renovated warehouse. Despite rhetoric by the Obama and Biden administrations promising to "close GITMO" - that discussion is really only about ending the detainee program, and the Naval Station, which has been under U.S. control through a lease with the Cuban government since 1903 is not in jeopardy of closing.
After visiting the gallery, reporters were taken into the large courtroom - approximately 100 feet by 100 feet - if not a little bigger.
The defendants have not been in the courtroom since early 2020 - just before the COVID-19 pandemic began. In addition to Mohammed, four other defendants charged in the 9/11 terrorist attacks will be in the courtroom: Walid bin Attash, Ramzi bin al-Shibh, Ammar al-Baluchi (also known as Abd al Aziz Ali) and Mustafa al Hawsawi.
The defendants will sit at five tables alongside their defense teams and interpreters - with Mohammed in the front - and his alleged co-conspirators seated from front-to-back in the order listed on the indictment and above.
Col. Matthew McCall will preside, becoming the fourth judge to sit on the bench during the pretrial proceedings. McCall was initially selected to oversee the trial last year, but withdrawn after prosecutors objected, citing his lack of experience. He was reinstated after completing two years as a military judge, meeting the minimum requirement for the war court.
At the base of each seat for the defendants are chains anchored into the carpet that could potentially be hooked to shackles if the judge determines a defendant must be restrained, although Wendy Kelly -- chief of operations at the Office of Military Commissions Guantanamo Bay -- did not believe this would be needed. There is also a hospital bed positioned in the back of the courtroom for a defendant in another trial.
A sixth table was built in the courtroom for a prospective sixth 9/11 defendant, although it will likely be unoccupied since the defendant was not indicted.
Timetable and priority on classified information
Protecting classified intelligence is a priority during the hearings. Information about events, location and timing could appear to be innocuous but combine to present a classified narrative. Kelly said the defendants have frequently sought to delay the proceedings by revealing classified information and details that they are privy to themselves.
The military commission is expected to have an open session all day Tuesday and a closed session on Wednesday, when none of the defendants will be permitted in the courtroom as the judge, defense and prosecution have a classified session. On Thursday, the court is expected to have an open session for a half day, and then another closed session on Friday. The pretrial proceedings are set to resume the following Monday and potentially carry on through Sept. 17.
What happens next is largely up to the discretion of the judge. He is expected to hold additional pretrial hearings later this year, but jury selection will not begin until 2022 at the earliest.
No video or audio from the courtroom will be released publicly, although an unofficial courtroom transcript will be posted approximately one day later, depending on the length of the proceedings and any potential security review for classification. There will be a sketch artist, who will be present in the soundproof gallery to draw images of the defendants in the courtroom. Kelly said that steps will be taken in the gallery to observe social distancing - with all attendees required to wear face masks. The judge must still determine whether to socially distance the defendants and their defense teams or ask them to wear masks.
Four out of five of the 9/11 defendants accepted an offer to receive vaccinations against COVID-19, and some personnel on the base have tested positive for the disease.
Approximately 10 remote-controlled video cameras are mounted on the walls and ceilings of the courtroom and Kelly assured ABC News that there are no hidden cameras in the courtroom.
To the far right of the courtroom is a box for the panel members - who serve as a jury and will be comprised of 12 military officers, with four alternates (although six may ultimately be chosen).
The pool of prospective jurors is comprised of hundreds of officers from all branches of the service. They are not expected to be sequestered during the trial, but may be asked by the judge not to read or view media reports on the trial, or the conduct interviews with the media. Kelly predicted it could take up to two months to vet and select prospective jurors.
Along the right side of the courtroom are several tables for the prosecution, which is also comprised of U.S. citizens - some civilian and some military. There is a podium in the middle of the courtroom that has a laptop computer and microphone. The podium swivels 360 degrees, so any speaker may turn to address the panel of military officers serving as the jury, for example.
There will be five 9/11 victim family members or survivors of the terrorist attacks - and each may bring one guest to accompany them in the gallery, as well as VFM (Victim Family Member) escorts. No recordings are allowed - so military security is present to ensure that nobody breaks the rules imposed by the military commission.
After viewing the courtroom, journalists were taken outside to view holding cells where the defendants will be detained during any recesses in the proceedings, as well as immediately before the day's proceedings commence. Reporters were permitted to peer into the cells but were prohibited from fully entering for security reasons.
Kelly said that detainees, who are held at the Joint Task Force miles from the courtroom, will be awoken about 5 a.m. each day, and then taken to the holding cells about 6:30 a.m. There are five cells, numbered ELC14 through ELC18. Inside each is a mounted bed with a foam cushion resting on a mattress. There are no sheets, after several detainees died by suicide years ago.
The cells also have a toilet and a Qibla pointer -- an arrow that points toward Islam's holiest site - the Kaaba in Mecca, Saudi Arabia. Monitors provide a closed-circuit feed to the defendants in each cell, if they decide not to remain in the courtroom or are removed for some reason.
There is also a larger holding cell nearby that can accommodate meetings with more members of the defense team. Between the larger holding cell and the five cells is another small building with a shower. There was also a make-shift shower positioned between cells ELC14 and ELC15. This was built on the site in case any of the defendants have to stay overnight at the ELC, and then later a more modern shower facility with additional privacy was added.
A thick black netting is designed to prevent anyone from the outside to see movements within. There was a long corridor leading from the detention cells to the courtroom, which the defendants will have to traverse in order to enter the courtroom.
Another building within the ELC is ready for any evidence introduced or entered into the record at the hearings - complete with digital servers. Nearly all of the evidence is digitally presented, although Kelly said there will also be physical evidence presented from the sites of the terrorist attacks. That physical evidence is possessed by the FBI in a locker across a courtyard in the ELC.