"Lord, all those around us search for motive, search for meaning, search for something, someone to blame. That is so frustrating," Col. Frank Jackson told a group of about 120 people gathered at one of the post's chapel. "Today, we pause to hear from you. So Lord, as we pray together, we focus on things we know."
Worshippers at the 1st Cavalry Memorial Chapel hugged each other and raised their hands in prayer during the service, in which Jackson asked the congregation to pray for the 13 dead and 29 wounded that Maj. Nidal Malik Hasan is accused of shooting. The chaplain also urged the crowd to pray for Hasan and his family "as they find themselves in a position that no person ever desires to be - to try and explain the unexplainable."
"Our prayer is that you will use us and this faith community to be a catalyst for healing and reconciliation," Jackson said. "Give us listening ears, open eyes and hearts, and confidence in the presence of your holy spirit as we journey together with all those around us through this valley of the shadow of darkness."
Meanwhile, a leading lawmaker said he plans to begin a congressional investigation to determine whether the shootings constitute a terrorist attack.
Sen. Joe Lieberman, chairman of the Senate Homeland Security and Governmental Affairs Committee, said on "Fox News Sunday" that he wants to find out whether the Army missed warning signs that Hasan was becoming extreme.
"If Hasan was showing signs, saying to people that he had become an Islamist extremist, the U.S. Army has to have zero tolerance," said Lieberman, an independent from Connecticut. "He should have been gone."
Across the sprawling post and in neighboring Killeen, soldiers, their relatives and members of the community struggled to make sense of the shootings. Candles burned Saturday night outside the apartment complex where Hasan lived. Small white crosses, one for each of the dead, dotted a lawn at a Killeen church on Sunday.
At least 16 victims remained hospitalized with gunshot wounds, and seven were in intensive care.
Even as the community took time to mourn the victims at worship services on and off the post, Fort Hood spokesman Col. John Rossi acknowledged that the country's largest military installation was moving forward with its usual business of soldiering. The processing center where Hasan allegedly opened fire on Thursday remains a crime scene, but the activities that went on there were relocated, with the goal of reopening the center as soon as Sunday.
Fort Hood is "continuing to prepare for the mission at hand," Rossi said. "There's a lot of routine activity still happening. You'll hear cannon fire and artillery fire. Soldiers in units are still trying to execute the missions we have been tasked with."
But the specter of the shooting lingers on the post. Rossi acknowledged that psychic wounds could be deep.
"The piece that most are troubled with right now is the location of where it happened and how it could happen," he said. "We know that problems sometimes take a while to manifest themselves in an individual and might come up in a later time period."
Military criminal investigators continue to refer to Hasan as the only suspect in the shootings but won't say when charges would be filed. Hasan, who was shot by civilian police to end the rampage, was in critical but stable condition at an Army hospital in San Antonio. He was breathing on his own after being taken off a ventilator on Saturday, but officials won't say whether Hasan can communicate.
A government official speaking on condition of anonymity because the person was not authorized to discuss the case said an initial review of Hasan's computer use has found no evidence of links to terror groups or anyone who might have helped plan or push him toward the attack. The review of Hasan's computer is continuing, the official said.
Army investigators on Sunday were searching for additional evidence to put together a comprehensive bullet trajectory analysis. Investigators were "seeking any military or civilian personnel who may have left the scene ... with gunshot damage such as damaged privately owned vehicles," Fort Hood spokesman Chris Haug said in a statement.
Hasan likely would face military justice rather than federal criminal charges if investigators determine the violence was the work of just one person.
John P. Galligan, an attorney who has represented Fort Hood soldiers but is not involved in the Hasan case, said a soldier can be in military custody until his case is disposed of unless his attorney complains of undue, lengthy delays. After a soldier is charged, he can be held in pre-trial confinement for 120 days before an attorney could raise complaints about delays.
Army Chief of Staff George Casey warned against reaching conclusions about the suspected shooter's motives until investigators have fully explored the attack. He said on ABC's "This Week" that focusing on Hasan's Islamic roots could "heighten the backlash" against all Muslims in the military.
There had been signs in recent months that Hasan's growing anger with the U.S. wars in Iraq and Afghanistan were at odds with his military service, including his comments that the war on terror was "a war on Islam." Others who knew Hasan, an Army psychiatrist, said he had wrestled with what to tell fellow Muslim solders who had their doubts about fighting in Islamic countries.
"I told him, `There's something wrong with you,"' Osman Danquah, co-founder of the Islamic Community of Greater Killeen, told The Associated Press on Saturday. "I didn't get the feeling he was talking for himself, but something just didn't seem right."
Danquah assumed the military's chain of command knew about Hasan's doubts, which had been known for more than a year to Hasan's classmates at a Maryland graduate military medical program. There, students complained to faculty about Hasan's "anti-American propaganda," but said a fear of appearing discriminatory against a Muslim student kept officers from filing a formal complaint.
Associated Press writers Jeff Carlton in Fort Hood and Devlin Barrett, Richard Lardner and Jessica Gresko in Washington contributed to this report.