A senior US law enforcement official has told CNN that U.S. intelligence believes that the principal author of the new online al Qaeda magazine is an American citizen who left for Yemen in October 2009.

The magazine – called "Inspire" – appeared last week. Running to nearly 70 pages, it included articles on bomb-making and encrypting electronic messages, as well as an interview with the fugitive Yemeni-American cleric, Anwar al Awlaki.

The source has identified the driving force behind "Inspire" as 23-year old Samir Khan, who previously lived in North Carolina and was involved in radical Islamist blogs, including one he ran called "Jihad Recollections." The source says Khan traveled to Yemen on a return ticket but has not come back to the United States. FULL POST