As if going off to war, Maj. Nidal Malik Hasan cleaned out his apartment, gave leftover frozen broccoli to one neighbor and called another to thank him for his friendship -- common courtesies and routines of the departing soldier. Instead, authorities say, he went on the killing spree that left 13 people dead. Investigators examined Hasan's computer, his home and his garbage Friday to learn what motivated the suspect, who lay in a coma, shot four times in the frantic bloodletting. Hospital officials said some of the wounded had extremely serious injuries and might not survive. The 39-year-old Army psychiatrist emerged as a study in contradictions: a polite man who stewed with discontent, a counselor who needed to be counseled himself, a...