Northwest Airlines bombing suspect Umar Farouk Abdulmutallab, the 23-year-old son of a wealthy Nigerian banker, became so politically extreme his own father reported him to U.S. authorities.
Tuesday, his family released a statement saying Abdulmutallab's "father, having become concerned about his disappearance and stoppage of communication while schooling abroad, reported the matter to the Nigerian security agencies about two months ago, and to some foreign security agencies about a month and a half ago, then sought their assistance to find and return him home."
The statement said that Abdulmutallab's recent behavior was "completely out of character and a very recent development, as before then, from very early childhood, Farouk, to the best of parental monitoring, had never shown any attitude, conduct or association that would give concern."
A senior U.S. official told ABC News that Abdulmutallab's father told the U.S. embassy in Nigeria his son had become radicalized and could pose a threat to the U.S.
More than 100 chat room posts traced to his e-mail account by ABC News show the course of his radicalization.
"I think this is the threat, the primary threat that we have to worry about now," said Richard Clarke, ABC News consultant and former counterterrorism czar. "People who've been radicalized in the United States, in Western Europe, people who have been radicalized long distance on the internet."
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."
Then 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."
Investigators believe Abdulmutallab was connected to al Qaeda by the same radical Yemeni cleric, American-born Anwar Awlaki, who is linked to American Army Major Nidal Hasan, accused of opening fire at Fort Hood in November.
"It appears that just like with Major Hasan, Awlaki played a role in this," said Rep. Pete Hoekstra, R-Mich, ranking minority member of the House Intelligence Committee. "All roads point back to Yemen, they point back to Awlaki, I think it is a pretty deadly combination."
Hoekstra said he will be looking into how Mutallab was radicalized, and whether he went to Yemen on his own initiative to meet members of al Qaeda.
Abdulmutallab's father was chairman of First Bank in Nigeria for ten years. He is currently chairman of Jaiz Bank, Nigeria's first Islamic bank.
Abdulmutallab was put on a terror watch list but his visa to visit the U.S., issued in 2008, was not revoked, nor was he put on the no fly list.
Said Rep. Hoekstra, "He should have been at the top of the no fly list."
Speaking on BBC Radio Tuesday morning, British Home Secretary Alan Johnson confirmed that Abdulmutallab had been placed on a U.K. watch list after he was refused a student visa 14 months ago. He explained that people on a watch list cannot come into the UK, although they can pass through the country in transit.
Johnson said that he did not believe Abdulmutallab had been acting alone, and that police and security services in Britain are examining whether he was radicalised while in London. They are looking at "what happened when he was in this country, was he radicalised in this country, was there any association with whoever may have been behind this plot. We don't know yet whether it was a single-handed plot or (there were) other people behind it - I suspect it's the latter rather than the former."
Abdulmutallab was arraigned on terrorism charges in federal court in Michigan on Saturday. His next expected court appearance is January 8.
Jean Fievet contributed to this report from London, Dana Hughes contributed from Nairobi.