This courtroom sketch shows military prosecutor Lt. Col. Steve Henricks, right, speaking as Nidal Malik Hasan, center, and presiding judge Col. Tara Osborn look on during his court-martial Tuesday, Aug. 6, 2013, in Forth Hood, Texas.
FORT HOOD, Texas — Maj. Nidal Malik Hasan fired the last of 146 bullets in his assault on Fort Hood, then walked outside where he met two civilians who asked about the commotion and the laser-sighted pistol in his hand.
Hasan told one person not to worry. He assured the other it was just a training exercise and the gun shot only paint. He let both live.
But moments earlier, dozens of uniformed soldiers received no quarter from Hasan, prosecutors said Tuesday as the Army psychiatrist's long-delayed trial began in a Texas military courtroom.
With his life hanging in the balance, Hasan made little effort to defend himself. Acting as his own attorney, he calmly told the jury that he killed 13 people and wounded 32 others in the 2009 attack.
"The evidence will clearly show that I am the shooter," he said in an opening statement that lasted little more than a minute The evidence, he added, would "only show one side."
His only utterance of regret was an acknowledgement that he was among "imperfect Muslims trying to establish the perfect religion."
"I apologize for any mistakes I made in this endeavor," said Hasan, an American-born 42-year-old who was paralyzed after being shot by officers responding to the attack. He spoke from a wheelchair, wearing green Army fatigues and a gray, bushy beard.
Hasan planned the assault for months, prosecutor Col. Steve Henricks said, describing how the defendant stockpiled bullets, practiced at a shooting range and bought an extender kit so his pistol could hold more bullets.
If convicted, Hasan could get the death penalty. No American soldier has been executed since 1961, and military prosecutors showed that they would take no chance of fumbling details that could jeopardize any conviction.
They described a calculating Hasan, armed with two handguns and carrying paper towels in his pants pockets to conceal the sounds of rattling ammunition as he walked through a deployment-readiness center on the sprawling base.
"He came to believe he had a jihad duty to murder his fellow soldiers," Henricks said, adding that Hasan had researched Taliban leaders' call to wage holy war.
The government has also said Hasan sent more than a dozen emails starting in December 2008 to Anwar al-Awlaki, a radical U.S.-born Islamic cleric killed by a drone strike in Yemen in 2011.
The shooting happened about three weeks after Hasan learned he would be deploying to Afghanistan. Upon getting the orders that he was going overseas, Hasan told a base doctor that, "They've got another thing coming if they think they are going to deploy me," Henricks said.
On the day of the attack, Hasan sat among his fellow soldiers who were preparing to go overseas. He tried to clear the area of civilians, even walking over to a civilian data clerk to tell her she was needed elsewhere in the building because a supervisor was looking for her. The prosecutor said the clerk thought that was odd but went anyway.
"He then yelled 'Allahu akbar!' and opened fire on unarmed, unsuspecting and defenseless soldiers," Henricks told the jury of 13 officers.
During Tuesday's proceedings, Hasan mostly looked down or straight ahead, occasionally leafing through paperwork while seated at the defense table. He spoke politely from his wheelchair, talking so softly at times that families of victims leaned forward to hear him.
Hasan declined to cross-examine any of the witnesses he shot or those who recounted his firearm purchases at a store called Guns Galore in nearby Killeen.
But he didn't pass on a chance to cross-examine his former supervisor, who had given Hasan high marks on an evaluation the very week of what Hasan would only call "the incident."