When Hasan began shooting, the troops were standing in long lines to receive immunizations and doctors' clearance. Thirteen people were killed and more than were 30 wounded. All but one of the dead were soldiers, including a pregnant private who curled on the floor and pleaded for her baby's life.
The attack ended only when Hasan was shot in the back by an officer responding to the shooting. Hasan is now paralyzed from the waist down and uses a wheelchair.
The military called nearly 90 witnesses at the trial and more during the sentencing phase. But Hasan rested his case without calling a single person to testify in his defense and made no closing argument. Even with his life at stake during the sentencing hearing, he made no attempt to question witnesses and gave no final statement to jurors.
Death sentences are rare in the military, which has just five other prisoners on death row. The cases trigger a long appeals process. And the president must give final authorization before any service member is executed. No American soldier has been executed since 1961.
Hasan spent weeks planning the Nov. 5, 2009, attack, including buying the handgun and videotaping a sales clerk showing him how to change the magazine.
He later plunked down $10 at a gun range outside Austin and asked for pointers on how to reload with speed and precision. An instructor said he told Hasan to practice while watching TV or sitting on his couch with the lights off.
When the time came, Hasan stuffed paper towels in the pockets of his cargo pants to muffle the rattling of extra ammo and avoid arousing suspicion. Soldiers testified that Hasan's rapid reloading made it all but impossible to stop him. Investigators recovered 146 shell casings in the medical building and dozens more outside, where Hasan shot at the backs of soldiers fleeing toward the parking lot.
In court, Hasan never played the role of an angry extremist. He didn't get agitated or raise his voice. He addressed the judge as "ma'am'' and occasionally whispered "thank you'' when prosecutors, in accordance with the rules of evidence, handed Hasan red pill bottles that rattled with bullet fragments removed from those who were shot.