WASHINGTON — A military judge on Friday set Jan. 11, 2021, as the start of the joint death-penalty trial at Guantánamo Bay of Khalid Shaikh Mohammed and four men charged with plotting the Sept. 11, 2001, attacks that killed 2,976 people in New York, Washington and Pennsylvania.
The date set by the judge, Col. W. Shane Cohen of the Air Force, signals the start of the selection of a military jury at Camp Justice, the war court convening at the Navy base in Cuba. It is the first time that a trial judge in the case actually set a start-of-trial date, despite requests by prosecutors since 2012 to two earlier judges to do so.
If the 2021 timeline holds, jury selection would start nine months before the 20th anniversary of the Sept. 11 attacks. One major issue the judge has yet to resolve is what evidence will be used at trial. He begins a series of hearings next month with witnesses in an effort by the defense teams to exclude confessions the defendants made to F.B.I. agents in early 2006 as tainted by the years of C.I.A. torture.
The judge’s instructions were included in a 10-page scheduling order that set deadlines toward reaching that trial date. As the first step, the prosecutors must provide the defense teams a list of materials by Oct. 1.
The five men are charged in a conspiracy case that describes Mr. Mohammed as the architect of the plot in which 19 men hijacked four commercial passenger planes and slammed two of them into the World Trade Center towers and one into the Pentagon, with one crashing into a Pennsylvania field. The other four men are described as helping the hijackers with training, travel or finances.
The charge sheets lists the names of the 2,976 people who died in the attacks.
The five men were captured in Pakistan in 2002 and 2003. The C.I.A. then held them incommunicado in its secret prison network, the black sites, where the United States tortured its prisoners with waterboarding, sleep deprivation and other abuse before delivering them to Guantánamo in 2006. That period has complicated the path to an actual trial.
The men were initially charged during the Bush administration at Guantánamo. President Barack Obama stopped that case and suspended the war court, known as military commissions, to overhaul it with Congress by adding more protections for due process. The case was also delayed by an Obama administration plan to try them in federal court in New York City, a proposal that drew political protests and legislation to prevent it.
Besides Mr. Mohammed, the other men charged are Walid bin Attash and Ramzi bin al-Shibh, who are described as deputies to carrying out the attacks — Mr. bin al-Shibh is described as having organized a cell of hijackers in Hamburg, Germany — as well as Ammar al-Baluchi, Mr. Mohammed’s nephew, and Mustafa al Hawsawi.
They were arraigned in this case on May 5, 2012.
Since then, the judges have held more than 30 pretrial hearing sessions to work out questions of law and evidence that would apply at the trial by military commission.
Another issue yet to be resolved is what protocols will be used to conduct magnetic resonance imaging of the five defendants to see if they suffered brain or other physical damage that defense lawyers might use to argue against their execution, if they are convicted. The judge gave the prosecutors until Oct. 1 to establish those.
Selection of the jury — 12 members and four alternate members — is expected to last months, with American military officers shuttled by air to and from the base in groups, because of cramped and limited housing at Guantánamo. Under the current timetable, that would mean that the prosecution’s presentation of the case itself could begin as the 20th anniversary of the terrorist attack approaches.
Because it is a national security case, the hearings are held in a special courtroom that lets people sitting behind the court in a spectator’s gallery watch live but hear the proceedings on a 40-second delay. Some of the tens of thousands of people who are victims or relatives of the Sept. 11 victims, including police officers and firefighters, have also been able to watch the proceedings through video broadcast to military bases in New York, Massachusetts and Maryland.
The war court itself is a hybrid of federal and military courts. Prosecutors work for both the Justice and Defense Departments. The five suspects have both military and civilian lawyers who are paid by the Pentagon.
Besides conspiracy, the men are charged with committing murder in violation of the law of war, attacking civilians and terrorism. Conviction can carry the death penalty, with the secretary of defense determining the method of execution.