Evan Kohlmann, a U.S. Justice Department consultant on al-Qaida and an NBC News analyst, said Benghazi’s reputation as a hotbed of Islamic militancy was cemented long ago.

“For more than two decades, a slice of eastern Libya near Benghazi, dominated by conservative bastions like the town of Derna, has served as a prolific incubator for local extremists, a surprising number of whom have surfaced as high-profile foreign combatants in conflicts ranging from Afghanistan, Bosnia, Chechnya, Iraq and now Syria,” he said…

An NBC News analysis of known al-Qaida leaders bears that out, indicating that the nearly 300-mile corridor between the desert and the Mediterranean Sea has produced more senior al-Qaida members than anywhere else in the Islamic world over the past seven years.