The man who claims to have orchestrated the Sept. 11 attacks is expected to appear in a military courtroom this Saturday. Khalid Sheikh Mohammed and four other men are supposed to answer formal charges related to their roles in the plot.

Their arraignment will be at Guantanamo Bay, and it is the first step that leads — possibly years from now — to a military trial.

Mohammed, also known as KSM, has admitted to masterminding the attacks. Still, there are indications that he and his four alleged co-conspirators will plead not guilty. That could mean a public airing of how he was treated in U.S. custody — details the government would rather not talk about.

The Lengthy Confession

Mohammed was in court in 2007 for a hearing to prove he still needed to be held at Guantanamo, that he still posed a threat to the U.S. as an enemy combatant.

He was fully engaged and actually addressed the court. In one instance, he objected to a particular piece of evidence. He said a computer hard drive that was being used against him wasn't his, explaining that it belonged to another detainee, Mustafa al-Hawsawi.

"This computer is not for me. [It is] for Hawsawi himself," Mohammed said. "Me and him, we were both arrested the same day, same way. This computer, it was for him for a long time. The problem is we are not in the court, and we are not [judges]; he's not a lawyer."

After a long session of grousing about the proceedings, Mohammed did an about-face. He asked his personal representative at the hearing — a kind of lawyer — to read a statement for him in which he admitted to everything and more.

"I hereby admit and affirm without duress to the following: ... I swore bayat, meaning allegiance ... to Sheikh Osama bin Laden," the representative said on Mohammed's behalf. "I was the media operations director. ... I was the operational director for Sheikh Osama bin Laden for the organizing, planning, follow-up and execution of the 9/11 operation. ... I was the military operational commander."

He took credit for the 1993 attack against the World Trade Center. He said he personally beheaded Daniel Pearl, the Wall Street Journal reporter who was kidnapped and killed in Pakistan in 2002.

The list went on and on. His representative spent literally six minutes listing all the plots.

What He Wanted The World To Know

Mohammed seemed to be presenting himself as the father of Islamic terrorism against the West, as the leader of a revolution to free Muslims.

"He likened himself at that confession to George Washington," says Terry McDermott, one of the authors of a new book called The Hunt for KSM.

McDermott has spent more than a decade tracking Mohammed through Dubai, Pakistan and Afghanistan.

He says Mohammed also made himself indispensable to al-Qaida.

"Al-Qaida was up to bad things with or without him, but a lot of the stuff we know that al-Qaida did would not have happened had it not been for him," McDermott says, "and I think he wanted the world to know that."

That's why, even though Mohammed has admitted to all of these plots, there is a chance that he will plead not guilty at his arraignment. That would force the U.S. to reveal the evidence it has against him and give Mohammed's defense the opportunity to describe CIA interrogations.

Introducing Torture To The Trial

The CIA has admitted to waterboarding three al-Qaida prisoners: Mohammed is one of them, and another is Ramzi bin al-Shibh, another defendant in the Sept. 11 trial.

Karen Greenberg, the executive director of the Center on National Security at Fordham University, says if Mohammed and the others plead not guilty, torture will become a centerpiece of the trial.

"When it comes to his confessions, they will say that whatever he confessed to happened after he was tortured," she says, "that whatever he says it's either because he still fears some sort of torture, or probably from a psychological point of view, he has some sort of post-traumatic stress disorder."

To make that argument, there will have to be testimony about the CIA's aggressive interrogations.

So far, only the sketchiest of details about those episodes have been released, and the rest is classified.

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