Anwar al-Awlaki, a cleric who allegedly played an operational role in al-Qaida, was killed in a 2011 drone strike in Yemen, along with his 16-year-old son and an alleged propagandist for terror groups. All three were American citizens. Al-Awlaki is shown here in an image taken from a 2010 video posted on radical websites. (SITE Intelligence Group, via AP)
