(CNN) -- Samir Khan was proud to be a traitor. In a way, he was among the most dangerous of al Qaeda terrorists. By turning his back on the country he grew up in, he gained credibility and coupled that with his intimate knowledge of Western culture to become a driving force behind a powerful al Qaeda propaganda machine.
The one-time North Carolina resident, who U.S. and Yemeni officials say was killed with Muslim cleric Anwar al-Awlaki in a drone strike Friday morning, used his knowledge of computers to help produce a glossy, Western-style magazine called Inspire that touted the edicts of al Qaeda in the Arabian Peninsula, or AQAP.
Just what motivates a man who has spent much of his life growing up in the United States to wage jihad against it? Many of the answers are provided by Khan himself in an article he penned for Inspire titled, "I Am Proud to Be a Traitor to America."
In the article, Khan details his journey from North Carolina to Yemen, writing that "Washington's imperialism" was something he could no longer tolerate. "What they have done and continue to do in the Muslim lands is what I felt, totally unacceptable to my religion."
He details how he relied on his U.S. right to free speech to become more vocal about his anger toward U.S. foreign policies. He also writes that he was aware he was being watched by the FBI, something that played a role in his decision to flee. (A senior law enforcement official tells CNN Khan was being investigated by the FBI office in North Carolina, which determined it didn't have enough evidence to seek an indictment against him.)
"I decided to take up the pen and write out my thoughts and feelings regarding America's cowboy behavior in the Islamic lands" wrote Khan. "I knew that I had to stay under the guidelines of the laws regarding freedom of speech, but at the same time, I knew the real truth wouldn't be able to reach the masses unless and until I was above the law."
Khan fled to Yemen in 2009 and intelligence officials believe it was soon afterward that he became the editor of Inspire magazine. The official explanation of Khan's presence in Yemen was that he had gone to "teach English," which had become code in intelligence circles for attending radicalization classes.
The publication of the magazine was also concerning to intelligence officials as it became a significant tool in AQAP's recruiting effort and a signified a dangerous shift by providing the know-how for sympathizers to carry out attacks.
"The primary focus of the magazine is to inspire individuals to not just fly to Yemen and join the group, but rather to provide them with the inspiration, the ideological framework, the targeting philosophy and the practical mechanics of building a bomb or conducting a shooting," said Ben Venzke, CEO of IntelCenter, a private company that provides intelligence analysis to governments.
"To do it all, without ever having to step foot in a training camp but never having to come in physical contact with a terrorist," Venzke said. "And this allows AQAP to not only conduct attacks against the U.S., but at no cost financially or in terms of security to the group, they are able to add this force multiplier to their operations, because if even one person follows the direction of the magazine, that's a great success."
The deaths of both al-Awlaki and Khan are believed to be a significant blow to the future of the magazine. Clearly, AQAP understood its value. In a recently released supplement to Inspire marking the anniversary of the 9/11 attacks, Khan identified an AQAP leader, Sheikh Abu Basir, as saying, "The media work is half of the jihad." He also quotes someone he describes as a "brother" as saying, "A powerful media production is as hard-hitting as an operation in America."
It's a significance not lost on intelligence professionals, who see Khan's death as a "two-fer," with al-Awlaki being the primary target.
"Khan is unique in the sense that like al-Awlaki, he spoke English and had an appeal to the Western mind. He knew how to write and had the technical ability to use the Web," said former U.S. National Security Adviser Fran Townsend, now a CNN contributor.
CNN Terrorism Analyst Peter Bergen added, "The fact that the editor of the magazine (Khan) has also been killed is a problem for al Qaeda in the Arabian Peninsula, particularly as it relates to their Western recruitment effort, because the two people who principally spoke to the Western world are now dead."
Townsend suggests intelligence officials will be looking closely at those who are willing to step up and fill the role -- that is, if AQAP can find anyone with the same command of the language and computer skills to do it. "That will be a strong indicator of how resilient the organization is," she said. "Over time, replacements tend to be less experienced."
In Charlotte, North Carolina, Khan family friend Jibril Hough told CNN that Khan's father did not agree with his son's views. "His father is feeling a number of emotions, not just today, but over the past few years," Hough said. "Emotions such as embarrassment, frustration and heavy sadness, because it was his son. Regardless of the disagreements that he had, it was his flesh and blood."
Hough, who runs an Islamic center where Samir Khan had occasionally prayed, expressed disappointment that the U.S. government opted to kill U.S. citizens who were not themselves known to be violent rather than capturing and trying them. "That is the American way -- or should be the American way."
CNN's Pam Benson, Joe Sutton and Terry Frieden contributed to this report