(CBS) FORT MEADE, MD - One of the men the United States government considers a high-value detainee pleaded guilty Wednesday to multiple terrorism-related charges, possibly making it easier for the government to proceed against other detainees. Majid Shoukhat Khan appeared before a military judge in Guantanamo Bay, Cuba to enter his plea of guilty to charges of murder in violation of the law of war, attempted murder, material support for terrorism and spying. Khan's sentencing will be postponed for four years, pending his cooperation in testifying against the other detainees. If he keeps his end of the deal, Khan faces a maximum of 19 years, with the clock beginning immediately. He has been in custody since March 2003. "If I keep my side of the bargaining, they keep their side of the bargaining," Khan said while talking with the judge, Col. James Pohl. While the judge said Khan's sentence could be reduced, he made it clear that Khan could face detention beyond his sentence. "I'm making a leap of faith here, sir, that's all I can do," Khan said. Khan was clean-shaven, wearing a suit and tie along with glasses, and spoke in English throughout the hearing. "Yes, sir," he told Pohl when asked if his plea was guilty. The hearing lasted close to three hours. After running through the various charges contained in the plea agreement and asking Khan whether he understood them and was making his plea voluntarily, Pohl delivered the final word: "Mr. Majid Shakout Khan, This commission finds you of all charges, guilty." Khan's guilty plea means he will likely become a key witness against other high-value detainees in custody at Guantanamo, including Khalid Sheikh Mohammed, the self-proclaimed mastermind of the 9/11 attacks. Because Mohammed and other detainees said the information used against them had been obtained by torture, Khan's testimony gives prosecutors another important way of building their cases against them, according to Karen Greenberg of Fordham University Law School. The military commission's indictment says that soon after arriving in Pakistan, Khan met with Mohammed. Khan pleaded guilty to murder and attempted murder for being part of a conspiracy that led to the bombing of the Marriott Hotel in Djakarta, Indonesia in August 2003. Khan had been captured by Pakistani authorities on March 1 of that year, but had delivered $50,000 in funds from KSM to some of those involved in planning the attack. Eleven people died and at least 81 were wounded in the bombing. Khan also pleaded guilty to attempted murder for a planned attack against then-Pakistani President Pervez Musharraf. Khan wore a suicide vest and went to a mosque where Musharraf was to appear, but he never arrived. The closed circuit feed from the hearing was briefly interrupted after Khan mentioned the CIA, saying he understood that with today's agreement he could not sue the agency. Earlier, Khan said he had been "illegally kidnapped." "I've never met Osama bin Laden," Khan said at one point during the hearing as the judge pointed out that he was part of the criminal conspiracy that included the al Qaeda leader, along with Mohammed and others.