Sources tell the CBS News investigative unit that they believe Umar Farouk Abdulmutallab communicated with Al-Awlaki while Abdulmutallab was a student in the United Kingdom.
Both men lived in London, though it is not clear whether their time there overlapped. Abdulmutallab apparently attended a talk by Al-Awlaki at London mosque, though Al-Awlaki, barred from entering Britain since 2006, addressed the meeting by video teleconference.
Since leaving the United States in 2002, Al-Awlaki has mainly lived in , where Abdulmutallab also .
Special Report: The Christmas Day Terror Attack
Investigators are looking at whether there was a relationship between them and whether the imam played a role in preparing him for martyrdom in this attack or had a role in the attack itself. Investigators believe Al-Awlaki may have helped him on his road to radicalization.
Al-Awlaki was born in the United States and moved back to Yemen in 2002. Al-Awlaki reportedly corresponded by e-mail with Maj. Nidal Malik Hasan, who is charged with killing 13 people at Fort Hood, Texas, on Nov.5.
Special Section: Tragedy at Fort Hood
Al-Awlaki denied inciting the army psychiatrist to carry out last November's deadly shootings at Fort Hood, instead pointing the finger of blame at the United States.
Known for his incendiary anti-American teachings, Al-Awlaki faulted American foreign policy for creating the conditions which ignited the rampage in which 13 were killed, according to the text of an interview posted on Aljazeera.net. An English translation of the Q&A was supplied to CBSNews.com by the Middle East Media Research Institute.
"I did not recruit Nidal Hasan to this operation; the one who recruited him was America, with its crimes and injustice, and this is what America refuses to admit," the cleric said. "America does not want to admit that what Nidal did, and what thousands of other Muslims do against America, is because of its unjust policies against the Islamic world. Nidal Hasan is a Muslim before he is an American, and he is also from Palestine, and he sees the oppression of the Jewish oppression of his people under American cover and support. True, I may have a role in his intellectual direction, but nothing beyond that, and I am not trying to absolve myself of what he did because I do not support it. No, but because I wish I had had the honor of having a bigger role in what happened than the role I really had."
Al-Awlaki and Hasan reportedly became acquainted when Al-Awlaki served as the imam of the Dar Al-Hijra Islamic Center in Falls Church, Va.
He said Hasan contacted him by email a year ago to ask whether the killing of American soldiers and officers could be justified as religiously legitimate, and that they continued their correspondence until the middle of this year.
Al-Awlaki earned degrees in engineering at Colorado State and in education leadership at San Diego State, according to his Web site. In addition to serving as an imam in northern Virginia, Al-Awlaki worked at a mosque in San Diego.
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Who Is Umar Farouk Abdulmutallab?
U.S. counterterrorism officials have closely watched him after finding evidence of contacts he had with three of the Sept. 11 hijackers.
Separately Tuesday, sources told CBS News that the FBI is in possession of a video of the attempted attack taken by a passenger onboard Flight 253. Authorities do not believe the person who took the video was in any way associated with Abdulmutallab.
The FBI would not confirm existence of such a tape, saying only that it spoke with all passengers on the flight and collected all available evidence.
"In this day and age, the fact that someone may have been filming is not surprising," FBI spokesman Bill Carter told CBS News. "We did interview every single passenger on the plane and anything of evidentiary value would've been taken."