In the video, the individual believed to be Maj. Nidal Malik Hasan appears wearing clothes that would be abnormal for someone of Palestinian descent - Hasan's family is from Jordan. CBS News correspondent Sheila MacVicar reports that the man is wearing a shalwar kameez - long robes far more common in Pakistan and Afghanistan.
He is also wearing white, which in Islam is associated with death or mourning. The prayer cap on his head is also more closely associated with Southeast Asia than with the Arab world.
Lt. Gen. Robert Cone, Fort Hood's base commander, told CBS's "The Early Show" that the alleged shooter is rumored to have said "Allahu Akbar," (God is great) during the shooting, but was unable to confirm that information.
If Hasan dressed like this commonly, it could have served as an indication that something was on his mind, notes MacVicar. His Imam in Virginia is quoted as saying he used to show up for prayers in his military uniform - so when he started donning the shalwar kameez could be an important clue as to his state of mind, and the direction of his thinking, explains MacVicar.
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Fast Facts: Fort Hood
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