Anwar al-Awlaki, a US citizen of Yemeni descent who was killed in a raid in Yemen last week, was a major figure in al-Qaeda's ranks, particularly in terms of his media persona. Security investigations and confessions from prisoners revealed that al-Awlaki's audio and video recordings in recent years played a key role in recruiting people to launch bloody attacks on al-Qaeda's behalf.

Al-Awlaki's importance went beyond his ability to recruit just anyone to al-Qaeda. It lay primarily in the fact that he and his operatives targeted a specific segment in their recruiting, namely English speakers and Muslims living in the West.

Al-Awlaki's death represents yet another severe setback for al-Qaeda, which now appears to have lost an essential voice that could disseminate propaganda to Muslims in the West.

In addition to losing an orator of al-Awlaki's calibre, who was known for his fluency in English and his prolific use of online media, al-Qaeda also lost a prominent staff member of Inspire magazine, which is geared to Muslims in the West. Yemen authorities suspect that Samir Khan, an American of Pakistani descent, was also killed in the same strike that killed al-Awlaki between the provinces of al-Jawf and Marib, 140 kilometres east of Sanaa.

Al-Awlaki played more than propaganda role

Even though al-Awlaki incited followers in his audio and video sermons and articles in Inspire magazine to kill Americans-- regardless of whether they were civilian or military, his role was not limited to publicity and promoting al-Qaeda's causes.

Security investigations and confessions from detainees in custody revealed he was also involved in plots to carry out killings, some of which had succeeded and some that failed. The day after he was killed, President Barack Obama described him as the director of "external operations" for al-Qaeda in the Arabian Peninsula branch, marking the first time al-Awlaki was described in such specific terms.

Subsequent investigations reported in the media revealed that al-Awlaki, 40, played a key role in the recruitment and training of the Nigerian student Umar Farouk Abdulmutallab, who was studying in Yemen and attempted to blow up a plan bound for the city of Detroit on Christmas Day 2009. The following year, al-Awlaki was allegedly also involved in a plot by the al-Qaeda branch in Yemen to detonate bombs aboard cargo planes headed to the United States. Also in 2010, his name was linked to a failed attempt to detonate a car bomb in New York's Times Square by a man who said al-Awlaki's speeches "inspired" him to carry out the attempt.

Al-Awlaki's inspiration would manifest itself again during the attempted murder of a British representative in the House of Commons by a woman who accused him of supporting the war in Iraq. The woman said she was influenced by al-Awlaki's statements.

Al-Awlaki was also implicated in the plot to murder US officers and soldiers at the hands of Nidal Hassan, a lieutenant colonel of Palestinian descent, at Fort Hood, Texas in 2009. Hassan and al-Awlaki communicated via e-mail multiple times before Hassan carried out his crime, which left 13 people dead.

Al-Awlaki called for murder of civilians

After al-Awlaki moved to Yemen and was released from prison in 2006, he stopped masking his radical stances that advocated killing, especially the killing of Americans, whom he began referring to as the "party of the devil", according to statements in one of his video recordings posted online in 2010. Al-Awlaki did not distinguish between civilians and military figures in his comments, calling for the outright murder of American civilians.

It is not clear whether al-Awlaki's efforts recruiting Muslims in the West through Inspire magazine and his speeches were based on instructions from al-Qaeda's central leadership on the Afghan-Pakistan border, or whether it was the brainchild of al-Qaeda in the Arabian Peninsula, led by Yemeni national Nasser al-Wuhaishi.

Al-Awlaki and Khan's deaths create void

Al-Awlaki's and Khan's absence will create a new dilemma for al-Qaeda. The severe shortage in senior members is preventing the organisation from filling many gaps in its ranks to replace those killed or arrested in various parts of the world, particularly in Pakistan and Afghanistan.

The organisation may re-assign the task of communicating with English speakers in the west to Adam Gadahn, an American who filled the role in the past. But such a move carries great risk because of the intense pressure being applied on al-Qaeda's main hideouts in Waziristan, particularly the raids by pilotless drones and Pakistani military operations in the region. The organisation may also decide to keep this role in the hands of its affiliate in Yemen if it can find other English speakers who may still be hiding in the country.

Regardless of whether al-Qaeda decides to keep its English language media apparatus in Yemen or move it back to Pakistan and Afghanistan, al-Awlaki's death will leave a huge void for the foreseeable future regarding its delivery of propaganda to Westerners. This is especially true in light of the continual depletion of the cadres, which is affecting its ability to find Arabic speakers to replace individuals who are killed or arrested, much less find fluent English speakers of al-Awlaki's calibre.