Why is Anwar Al-Awlaki terrorist 'No. 1?'

United States officials have known about a young Muslim cleric named Anwar al- Awlaki at least since the 9/11 terrorist attacks. The 9/11 commission, in its report about the Al Qaeda strike, said Mr. Awlaki and two hijackers aboard American Airlines Flight 77 (which crashed into the Pentagon) were part of a small group of "ideologically like-minded" individuals who kept company for a time in the US prior to 9/11.

Lately, Awlaki's profile has come front and center, with reports that he is linked to three terrorism cases in the US in the past year. Here is an overview of what's known about Awlaki and what the Obama administration intends to do about him.

What is Awlaki's alleged role in recent terrorist plots against the US?

US officials say Awlaki's fingerprints are on three attacks or attempted attacks against the American homeland: the Fort Hood shooting in Texas in November, the Christmas Day bombing attempt of a Detroit-bound airliner, and the botched Times Square car bomb in New York on May 2.

•Investigators of the Fort Hood shooting, in which 13 were killed and 30 wounded at the Army base, say suspect Nidal Hasan and Awlaki exchanged at least 18 e-mails in the year leading up to the shooting. Awlaki's role, they say, appears to have been to inspire Hasan to act.

•The alleged Christmas Day bomber, Umar Farouk Abdulmutallab, received training in Yemen from Al Qaeda on the Arabian Peninsula, and he is believed to have met Awlaki there. Awlaki himself reportedly acknowledged to a Yemeni journalist that he met Mr. Abdulmutallab last fall but denied any role in the plan to bring down the plane.

•Faisal Shahzad, who is charged in connection with the car-bomb attempt in Times Square, allegedly told officials he was inspired by Awlaki's violent rhetoric, which is accessible on the Internet.

What's Awlaki's background?

Awlaki was born in New Mexico in 1971 to Yemeni immigrants, making him an American citizen. He was raised from age 7 in Yemen but returned to the US to attend college in Colorado and California, studying engineering and then education. But he did not pursue careers in those fields, opting instead for the life of a cleric. He served in two mosques, in San Diego and then Falls Church, Va., between 1995 and 2002. According to news reports, his friends said he was distressed by the government's treatment of Muslims after 9/11. He moved to London soon thereafter, where he traveled as a lecturer. He left for Yemen in 2004. He was imprisoned there for 1-1/2 years and released due to lack of evidence in late 2007.

Why did Awlaki adopt a radical version of Islam and turn against the US?

That's not entirely clear. In a sermon Awlaki delivered in his Virginia mosque soon after 9/11, he said Muslim Americans "came here to build, not to destroy. We are the bridge between Americans and one billion Muslims worldwide," according to a recent New York Times report. But afterward, he became more critical of Western values. Certainly, Awlaki did not approve of the US-led war in Iraq. At a London mosque in 2003, he preached that "Iraq is being devoured" and that "we cannot allow such things to happen and just watch," according to the Times. His father told CNN in January that his son became more radical after his time in prison. Last fall, after the Fort Hood shootings, Awlaki posted a statement on his now-defunct website that said Major Hasan, the Army psychiatrist charged in the case, is a "hero" and a "man of conscience" who could not live with the contradiction of serving in an Army that was fighting his own people.

Does Awlaki belong to a terrorist group?

Though increasingly radical in his speech, Awlaki did not appear to be affiliated with any terrorist organization. In recent months, however, at least one communication attributed to Awlaki carried the insignia of Al Qaeda on the Arabian Peninsula. AQAP is a relatively new organization, formed after two Yemen-based Al Qaeda groups joined forces in January 2009. Its leaders, Nasir al-Wahishi and military commander Qasim al-Rimi, are considered Yemeni extremist leaders, according to the National Counterterrorism Center, a US government agency. But Awlaki may now be the most well-known member of the group, which for years focused its attacks within Yemen but now appears to be turning outward.

Educated, English-speaking, familiar with American culture, Awlaki has gained prominence as a global jihadist, using the Internet to try to spread his ideas – including inside America. "He is very fluent in his use of the Internet and e-mail" to communicate his "theological justifications for jihad," says Richard Fontaine of the Center for a New American Security in Washington. Facebook contains three sites that appear to be Awlaki's, including one with 155 fans. At least a dozen video postings of his sermons or other entries are on YouTube.

News reports cite unnamed US officials as saying Awlaki has moved from an inciting actor to an "operational" one who plans attacks and recruits people to carry them out. Any evidence supporting that claim, however, has not been made public.

Is Awlaki America's most wanted?

Rep. Jane Harman (D) of California, chair of a House intelligence subcommittee, recently called Awlaki "terrorist No. 1" in terms of the threat he poses to the homeland.

President Obama earlier this year took the unusual – and controversial – step of authorizing "capture or kill" operations against Awlaki, despite the cleric's standing as a US citizen. Predator drones flying over Yemen, where Awlaki is believed to be, are monitoring his prospective hiding places.

Yemen is quietly helping with the manhunt. But Yemen's leaders are careful not to appear to be doing Mr. Obama's bidding, so as not to lose credibility among Yemenis. Recently, Yemen's foreign minister said that if Awlaki is captured, he would be put on trial in Yemen, where he is also wanted, not extradited to the US.

While the US has signaled its urgent intent to take Awlaki out of circulation, analysts caution that there are many dangerous individuals urging and orchestrating violence against the US.

"There are a lot of creatures like him," says Steven Simon, a senior fellow at the Council on Foreign Relations, who served on the National Security Council under President Clinton. "There is so much inspiration for violence out there, it's hard to gauge his contribution according to some metric."

Related:

Anwar al-Awlaki: Is it legal to kill an American in war on terror?

US-born cleric inspired Times Square bomber Faisal Shahzad

Fort Hood shooting: Was Nidal Malik Hasan inspired by militant cleric?