More than 100 chat room posts traced to his e-mail account by ABC News show the course of his radicalization. In high school Abdulmutallab described himself as "very ambitious and determined."
He was concerned he would not get into college at Caltech, Stanford or Berkeley because of his test scores.
"I tried the SAT. It was a disaster!!! I didn't practice well and I got 1200." Abdulmutallab attended college in London between 2005 and 2008.
He wrote of being lonely and sought friends on-line. "Can you be my friend?" he wrote. "I get lonely sometimes because I have never found a true Muslim friend."
Later, he wrote of joining protests against the war in Iraq, asking "when is lying allowed to deceive the enemy?" Still later he wrote of heading to Yemen.
"The Obama administration has been admitting lately, that Yemen is the new Afghanistan," said Clarke. "It is the new sanctuary. The new al Qaeda base, where people from around the world, who want to be trained are sent. No longer to Afghanistan, but to Yemen."
Videos released by al Qaeda in 2010 showed Abdulmutallab and others in his training class in Yemen firing weapons at a desert camp whose targets included the Jewish star, the British Union Jack and the letters "UN." The tape also included an apparent martyrdom statement in Arabic from the then 23-year old justifying his actions against "the Jews and the Christians and their agents." He says, "the enemy is in your lands with their armies, the Jews and the Christians and their agents." He reads several passages from the Koran and adds, "God said if you do not fight back, He will punish you and replace you."
U.S. officials believe Abdulmutallab left Yemen in mid-December of 2009 on his suicide mission.