Khalid Sheik Mohammed, called KSM, is accused of masterminding the Sept. 11 attacks by proposing the idea to Osama bin Laden in 1996, overseeing the operation, and training the hijackers in Afghanistan and Pakistan. The International Committee of the Red Cross says Pakistani authorities arrested him March 1, 2003 in Rawalpindi, Pakistan. The CIA subjected him to an interrogation technique called waterboarding before his 2006 transfer to Guantánamo Bay. In March 2007, according to a military transcript, he boasted: ''I was responsible for the 9/11 operation -- from A to Z."

Walid bin Attash allegedly ran an al Qaeda training camp in Logar, Afghanistan, where two of the 19 Sept. 11 hijackers were trained. Osama bin Laden allegedly selected him as a Sept. 11 hijacker but he was prevented from participating when he was arrested and briefly detained in Yemen in early 2001. The Pentagon also says he traveled to Malaysia in 1999 to study U.S. airline security. The ICRC says Pakistani authorities arrested him on April 29, 2003 in Karachi, Pakistan.

Ramzi bin al Shibh, a Yemeni, allegedly helped the German cell of hijackers find flight schools and enter the United States, and helped finance the operation. He allegedly was selected to be one of the hijackers and made a ''martyr video," but was three times denied a visa at the U.S. Embassy in Berlin. The ICRC says Pakistani authorities arrested him Sept. 11, 2002 in Karachi, Pakistan. A military, court-appointed medical panel has found he suffered from mental illness in the past and may still.

Ammar al Baluchi, also known as Ali Abd al Aziz Ali, is alleged to have sent approximately $120,000 to the hijackers for their expenses and flight training, and helped nine of the hijackers travel to the United States. He is believed to have served as a key lieutenant to Khalid Sheik Mohammed in Pakistan. He was born in Pakistan's Baluchistan province, raised in Kuwait, and is KSM's nephew. The ICRC says Pakistani authorities arrested him on April 29, 2003 in Karachi, Pakistan. His U.S.-educated wife, Aafia Sidiqqui, was captured in Afghanistan but unlike her husband was taken to New York City for trial and conviction on attempted murder charges and is now serving and 86-year sentence.

Mustafa Ahmad al Hawsawi, a Saudi, is alleged to have helped the hijackers with money, Western clothing, traveler's checks and credit cards. The ICRC says Pakistani authorities arrested him March 1, 2003 in Rawalpindi, Pakistan. Hawsawi served as a witness in the Zacarias Moussaoui trial, saying he had seen Moussaoui at an al Qaeda guesthouse in Kandahar, Afghanistan, in the first half of 2001, but was never introduced to him nor conducted operations with him.

Army Col. Stephen Henley was the earlier trial judge. A military judge since 1998, he took over the complex conspiracy mass murder case in November 2008, five months after the men were arraigned. Henley got his law degree, specializing in environmental law, from George Washington University. He was earlier assigned to preside in the military commission case of an Afghan accused of throwing a grenade at U.S. forces in Kabul in December 2002, and in that case became the first commissions judge to exclude a confession on grounds the U.S.-held detainee had been tortured, in that instance by allied Afghan police. He has prosecuted felonies in the DC Superior Court as a special assistant U.S. Attorney in the DC Superior Court, from 1990 to 1991 and has been a military judge at Fort Hood, Texas, Manheim, Germany and Fort Bragg, N.C. He also presided at the 2007 Fort Meade, Md., court martial of an Army officer accused in the case of abusing detainees at Abu Ghraib, Iraq. As of October 2011 it was not known who would succeed him as presiding judge in the new phase of the case.

Charges include conspiracy in the Sept. 11 attacks, specifically with Osama bin Laden, other senior al Qaeda members and the hijackers, plus eight other charges including murder in violation of the law of war, attacking civilians, and providing material support for terrorism. Mohammed, bin Attash, Bin al Shibh and Baluchi are also charged specifically with hijacking four aircraft -- two that hit the World Trade Center towers in New York, the one that hit the Pentagon and the one that crashed in the western Pennsylvania countryside. According to the Pentagon, the attacks killed 2,976 people

The sworn charge sheet

The Pentagon has built a $12 million Expeditionary Legal Complex with a snoop-proof courtroom capable of trying six alleged co-conspirators before one judge and jury. Media and other observers are sequestered in a soundproofed room behind thick glass, at the rear. The judge at the front and a court security officer have mute buttons to silence the feed to the observers' booth -- if they suspect someone in court could spill classified information.

More about the special court

The lead 9/11 case prosecutor during the Bush era was retired Army Col. Robert Swann, formerly the Pentagon's chief prosecutor for military commissions. The rest of his 9/11 prosecution team included: Edward Ryan, a civilian attorney with the Department of Justice; Clayton G. Trivett Jr., a retired Navy lieutenant currently a civilian employee of the Department of Defense; George Toscas, Thomas P. Swanton and Jordan Goldstein of the Department of Justice and Jeffrey Groharing, a former U.S. Marine lawyer who left service to work at the Justice Department.