Their word alone. Nasr al-Ansi, a militant commander, made the claim in a video released this week.
Iman University, a Sunni religious school in Yemen, educated US Taliban member John Walker Lindh and gave a teaching post to militant American preacher Anwar al-Awlaki. The school denied rumors that it hosted "underwear bomber" Umar Farouk Abdulmutallab, but concern over its militant ties are growing.
Investigations into where alleged Northwest Airlines bomber Umar Farouk Abdulmutallab got his explosives point toward Yemen and its local Al Qaeda offshoot. Foreign Policy Magazine's latest Failed State Index named Yemen as particularly troubling.
Alleged Fort Hood shooter Major Nidal Malik Hasan had ties to US-born militant Moslem cleric Anwar al-Awlaki, a leading figure seeking to recruit English speakers to violent jihad.