The Army psychiatrist suspected of being the lone gunman in a horrific massacre at Fort Hood in Texas took a "very calm and measured approach" to carrying out the mass shooting, the commanding general said Friday.
Survivors of the rampage that killed 13 and wounded 30 said the suspect, Major Nidal Malik Hasan, shouted "Allahu Akbar!" — "God is great!" in Arabic — before opening fire, base commander Lt. Gen. Robert Cone said.
Cone said officials had not yet confirmed that Hasan, 39, made the comment. Authorities searched his apartment early Friday for clues but haven't yet been able to talk to Hasan, who survived the shootings and was hospitalized on a ventilator.
Federal authorities seized Hasan's computer Friday. It was not immediately known if FBI agents found anything suspicious on Hasan's computer files.
A military official said investigators also are sifting through materials Hasan carried with him during the shooting incident and evidence left in his vehicle, which was found parked at the base.
Military officials were piecing together what pushed a man who helped troubled soldiers to turn on his comrades. The Army wouldn't discuss a motive in an early-morning press conference, but initial reports suggested he feared his imminent deployment to Afghanistan and had been critical of the wars there and in Iraq.
"He was mortified by the idea of having to deploy,” Hasan's cousin Nader Hasan told The New York Times. “He had people telling him on a daily basis the horrors they saw over there.”
Federal law enforcement officials told The Associated Press that Hasan had come to their attention at least six months ago because of Internet postings that discussed suicide bombings. The officials said they are still trying to confirm that he was the author.
One of the Web postings that authorities reviewed is a blog that equates a suicide bomber to a soldier throwing himself on a grenade to save the lives of his comrades.
"To say that this soldier committed suicide is inappropriate. Its more appropriate to say he is a brave hero that sacrificed his life for a more noble cause," the Internet posting reads. "Scholars have paralled (sic) this to suicide bombers whose intention, by sacrificing their lives, is to help save Muslims by killing enemy soldiers."
Hasan was working with soldiers at Darnall Army Medical Center on Fort Hood after being transferred in July from Walter Reed Army Medical Center, where he had worked for six years before recently receiving a poor review.
Cone said the shooter used two guns, including a semi-automatic weapon. He added there was no indication they were military weapons.
"We are trying to make sense of all this," the suspect's cousin told Fox News. "He wasn't even someone who enjoyed going to the firing range."
Hasan was not known to be a threat or risk, Fort Hood officials said.
"We had no problems with job performance while he was working at Darnall," said Col. Steve Braverman, Fort Hood's hospital commander. When pressed, Braverman added, "Not here. ... I'm not aware of any problems here."
Thursday's massacre was the worst mass killing ever to take place on a U.S. military base. A female civilian police officer identified as Kim Munley who shot Hasan was the one who stopped the spree. She survived, contrary to earlier reports that she had died.
An imam from a mosque Hasan regularly attended said Hasan, a lifelong Muslim, was a committed soldier, gave no sign of extremist beliefs and regularly wore his uniform at prayers.
Cone said witnesses spoke of the methodical way Hasan conducted the rampage. About 300 soldiers were lined up to get shots and eye-testing at a Soldier Readiness Center when gunfire erupted.
"It seems like a very high number of people for a single shooter," Cone told Fox News Friday. "This is a very small area. ...In talking to the soldiers last night who were present, the shooter could move in very close distances and fire at very close range and hit a number of people.
With the problem of ricochet fire, et cetera, he was able to injure that number of people."
All but two of the injured were still hospitalized, including Hasan, and all were in stable condition, Braverman told reporters.
One soldier who was shot said that he "made the mistake of moving and I was shot again," Cone told CBS' "The Early Show." Those present during the massacre "would scramble to the ground and help each other out," he added.
Braverman said at a news conference early Friday that Hasan was on deployment orders to Afghanistan. A military official later told The Associated Press that Hasan was to be deployed to Iraq. It was not immediately possible to verify the discrepancy.
The military official, who did not have authorization to discuss the matter publicly and spoke to the AP on condition of anonymity, said Hasan had indicated he didn't want to go to Iraq but was willing to serve in Afghanistan.
A neighbor at the apartment building near Fort Hood where Hasan lived said they had recently discussed his impending deployment to Afghanistan.
"He seemed OK with it," said Edgar Booker, a 58-year-old retired soldier who now works in a cafeteria on the post. "I asked him how he felt about going over there, with their religion and everything, and he said, `It's going to be interesting."'
Hasan was unconscious in a hospital after being shot four times at the Army's sprawling Fort Hood post, officials said. In the early chaos after the shootings, authorities believed they had killed him, only to discover later that he had survived.
A police source told FoxNews.com that Hasan's vital signs failed while he was being transported by ambulance to the hospital after the rampage but he was revived.
Federal law-enforcement agents ordered an evacuation of the apartment complex where Hasan lived in Killeen, Texas, and conducted a search of his home, said Hilary Shine, director of public information for the city. She didn't say what was found during the search.
Before Thursday's shooting, Hasan reportedly gave away all of his furniture along with copies of the Koran to neighbors, KXXV-TV reported.
Authorities have not ruled out that Hasan was acting on behalf of some unidentified radical group, a senior U.S. official in Washington said. He would not say whether any evidence had come to light to support that theory.
The motive for the shooting remained a mystery, but Hasan was apparently set to deploy soon, and had expressed some anger about the wars in Iraq and Afghanistan.
Sen. Kay Bailey Hutchison, R-Texas, said generals at Fort Hood told her that Hasan was about to deploy overseas.
Retired Army Col. Terry Lee, who said he worked with Hasan, told Fox News that Hasan had hoped President Barack Obama would pull troops out of Afghanistan and Iraq. Hasan got into frequent arguments with others in the military who supported the wars, Lee said, and had tried hard to prevent his pending deployment.
Two other soldiers who were taken into custody for questioning were later released, Cone said.
Soldiers rushed to treat their injured colleagues by ripping their uniforms into makeshift bandages. Officials have not ruled out the possibility that some casualties may have been victims of "friendly fire," shot by authorities amid the mayhem and confusion at the scene, said a senior U.S. official who spoke on condition of anonymity to discuss matters that were under investigation.
Video from the scene showed police patrolling the area with handguns and rifles, ducking behind buildings for cover. Sirens could be heard wailing while a woman's voice on a public-address system urged people to take cover.
"I was confused and just shocked," said Spc. Jerry Richard, 27, who works at the center but was not on duty during the shooting. "Overseas you are ready for it. But here you can't even defend yourself."
Soldiers at Fort Hood don't carry weapons unless they are doing training exercises.
The shooting took place 1:30 p.m. Thursday at the Readiness Center, where soldiers undergo medical screening before being deployed or after returning from overseas.
"We have a terrible, tragic situation here," said Cone. "Soldiers, family members and the civilians that work here are absolutely devastated."
Cone said the injuries "vary significantly" among the victims wounded in the shooting.
The shooter's cousin told Fox News that their family is in shock.
He said his cousin, who was born and raised in Virginia and graduated from Virginia Tech University, turned against the wars after hearing the stories of those who came back from Afghanistan and Iraq.
Nader Hasan said his cousin, who was raised a Muslim, wanted to go into the military against his parent's wishes — but was taunted by others after the terror attacks of Sept. 11.
A former neighbor of Hasan's in Silver Spring, Md., told Fox News he lived there for two years with his brother and had the word "Allah" on the door.
She said the FBI interviewed her Thursday afternoon, adding she used to see a woman and a 3-year-old girl coming and going.
Authorities provided little information Thursday about the victims of the rampage at Fort Hood.
George Stratton's son, George Stratton III, was five feet away from the shooter at the Soldier Readiness Center and suffered a gunshot wound to his left shoulder.
"He said he was there doing medical stuff and all of a sudden someone came through the door, walked behind the desk and just started shooting," Stratton told FoxNews.com.
He said about 15 rounds went off and people started dropping to the floor.
"He peaked up over the desk and that's when he was shot in the shoulder, and he just went down again. He said he saw one of his NCOs get badly shot," Stratton told FoxNews.com after talking to his son in the hospital. "After he got shot he told me, 'Dad, I got up, held my arm and took off running.'"
Stratton said his son was expected to be deployed to Afghanistan in January after going to basic training exactly a year ago.
"It's pretty hard to believe something like this happened," Stratton told FoxNews.com. "I think he's probably had his fill of war already."
President Obama called the shooting a "horrific outburst of violence" on members of the nation's armed forces. "It is horrifying that they should come under fire at an army base on American soil," he said
Obama said his thoughts and prayers are with the wounded and families of the fallen.
A spokesman for the Council on American-Islamic Relations said they don't know anything about Hasan, and condemned the shooting at Fort Hood.
The group issued a statement calling the shooting as a "cowardly attack." They say no political or religious ideology could ever justify or excuse such violence.
The base and area schools were on lockdown after the mass shooting, and all those on the Army post were asked to gather for a head count, thought the lockdown was lifted Thursday night.
Covering 339 square miles, Fort Hood is the largest active duty armored post in the United States. Home to about 52,000 troops as of earlier this year, the sprawling base is located halfway between Austin and Waco.
FoxNews.com's Jana Winter, Catherine Donaldson-Evans, Michelle Maskaly and The Associated Press contributed to this report.