Nine years after he was captured, Abd al-Rahim al-Nashiri was finally arraigned on charges of murder, terrorism, and hijacking.
He's accused of masterminding the 2000 bombing of the USS Cole that killed 17 sailors in Aden harbour in Yemen.
If convicted, he could face the death penalty. During the military commission proceedings in a courtroom at Guantanamo Bay, Nashiri was asked if he wanted to enter a plea.
Through his lawyers, he said he wouldn't enter a plea in Wednesday's hearing and reserves the right to challenge the charges against him. Nashiri was dressed in his white detention uniform, with short hair and no beard.
Throughout the proceedings, he listened and often stroked his chin. Judge Army Colonel James Pohl asked Nashiri if he needed an interpreter.
Nashiri replied in English, "of course, yes." Most of the rest of the time the Saudi citizen spoke in Arabic.
Nashiri has been detained at Guantanamo Bay since 2006. Before that he was the victim of waterboarding by the CIA at a black site.
He was subjected to extraordinary rendition. CIA documents indicate he endured mock executions and had a power drill held to his head.
During the four hour proceedings, the lead defence attorney, Richard Kammen, pressed the judge to find out his views on the death penalty and hearsay evidence.
Judge Pohl said he'd follow the law, saying "rules are rules, I’m a simple guy."
Nashiri instructed Kammen, whom he calls Mr Rick, to ask the judge if he thinks he's guilty. Judge Pohl answered by saying he's presumed innocent.
The proceedings are seen as a test case for the 9/11 trials.
The Obama administration and Congress revamped the military commissions system criticised under the Bush administration because they lacked transparency and didn't provide due process.
Under the new rules, no evidence gained by torture is admissible.
The proceedings are more open as well. Journalists, family members of the victims, and the general public were allowed to view the proceedings on a 40- second delay via closed circuit TV in the US.
But critics of the military commissions ask if Nashiri can get a fair trial at all.
Steven Vladeck, of American University, says: "At some point there's going to be a judge who will wonder whether a criminal conviction based on evidence tainted with these allegations can be upheld consistently with constitutional principles."
The two sides agreed the trial would begin in a year, on November 9, 2012.
But afterwards, Kammen said he thought it would take much longer to prepare a defence.
They've received none of the evidence yet which they will have to refute.
He said they should receive half a million pages of information. Family members of victims of the USS Cole bombing who attended the arraignment spoke to reporters when the arraignment was over.
John Clodfelter, whose son died in the blast, said: "When we first saw him, he was a pitiful looking person. I wanted to face him and show him he hadn’t gotten away with it."
A verdict and the appeals process could take many more years. And even if the jury, which will be made up of military officers, acquits Nashiri, he could still be detained indefinitely.
The government has indicated they believe they can keep him locked up regardless of the outcome of the case.