Shortly after the attack on the U.S. diplomatic compound in Benghazi last September, a phone call was placed from the area. Whoever made the call was excited. "Mabruk, Mabruk!" he repeated, meaning "Congratulations" in Arabic. Two sources with high-level access to Western intelligence services have told CNN the call was made to a senior figure in al Qaeda in the Islamic Maghreb, or AQIM. There is no proof that the call was specifically about the attack, in which U.S. Ambassador Chris Stevens and three other Americans were killed, but the sources say that is the assumption among those with knowledge...