Umar Farouk Abdulmutallab has admitted trying to detonate an explosive device on a Dec. 25, 2009, flight from Amsterdam to Detroit.
Al-Qaida leader Anwar al-Awlaki personally directed and approved the attempted bombing of a U.S. airliner that a Nigerian man tried to carry out on Christmas 2009, according to new details released by federal prosecutors on Friday.
Awlaki was a leader of al-Qaida in the Arabian Peninsula, the militant group's affiliate in Yemen, before he was killed in a drone strike last year. Awlaki directed Umar Farouk Abdulmutallab to carry out a strike aboard an American airliner over U.S. soil, prosecutors say.
"Awlaki's last instructions to him were to wait until the airplane was over the United States and then to take the plane down," according to court papers. Awlaki left it up to Abdulmutallab to pick the flight and date, the papers said.
Abdulmutallab, 25, is due to be sentenced Thursday in Detroit and faces up to life in prison after pleading guilty to charges he tried to down a Northwest Airlines jumbo jet with 289 people aboard on a flight from Amsterdam to Detroit.
The bomb, hidden in his underwear, failed to fully detonate and he was subdued. The incident led U.S. security officials to quickly bolster airport security, deploying full-body scanners to try to detect explosives hidden in clothing.
In urging the federal court to impose a life sentence on Abdulmutallab, federal prosecutors Friday revealed new details about his contact in Yemen with Awlaki.
“This removes any doubt that Anwar al-Awlaki was directing this operation from soup to nuts,” a White House official said Friday, according to NBC News, Some civil libertarians have said the U.S. lacked legal authority to kill Awlaki, who was a U.S. citizen.
“Congress has clearly granted the authority to target U.S. citizens who take up arms against the United States,” the official said.
Among the details, according to prosecutors:
Abdulmutallab followed Awlaki's online teachings for several years and went to Yemen in 2009 hoping to arrange a meeting. He visited mosques and asked people he met if they knew how he could meet Awlaki, eventually finding someone who offered to help.
He received a text message from Awlaki and the two later talked by phone. After sending a long message about why he wanted to engage in jihad, Abdulmutallab was cleared to meet Awlaki and was driven through the desert to Awlaki's house, where he stayed for three days, discussing martyrdom.
He was then driven to another house, where he met Ibrahim al-Asiri, the bomb maker for al-Qaida in Yemen. They talked about a plan for the terrorism mission, and Abdulmutallab was trained in al-Qaida camp.
Al-Asiri made the underwear bomb, delivered it to Abdulmutallab, and told him how to detonate it -- by pushing the plunger of a syringe that would mix two chemicals, starting a fire, and setting off the main explosive charge.
Abdulmutallab recorded a five-minute martyrdom video and left Yemen, with the authority to choose the flight and date to attack.
In October, Abdulmutallab pleaded guilty days after his trial began, saying he commited the crime because he wanted to avenge the killing of innocent Muslims by the United States.
In a sentencing memorandum filed in federal court in Detroit, prosecutors urged a judge to sentence Abdulmutallab to the maximum of life in a U.S. prison.
Obama administration officials said the information about Abdulmutallab’s activities in Yemen were obtained from his interrogation by an FBI agent.
“This demonstrates that it’s not necessary to charge terrorists as enemy combatants and put them before military tribunals in order to gain valuable intelligence,” a White House official said Friday.
NBC News Chief Justice Correspondent Pete Williams and Reuters contributed to this story.
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