Over the last few weeks, Maj. Nidal Malik Hasan drove off the vast Army base at Ft. Hood, Texas, at least a dozen times to enjoy seafood dinners with Duane Reasoner Jr., an 18-year-old he was mentoring in the ways of Islam.
They would pray at the simple Masjidu-Ttaqwa prayer hall out along the highway, hit the all-you-can-eat buffet at the Golden Corral and then rush back for evening worship. Twice they drove to Hasan's one-bedroom apartment to pick up books or to talk.
Only once -- on Wednesday, the night before Hasan allegedly shouted, "Allahu akbar!" pulled out two guns and opened fire on dozens of fellow soldiers -- did the dinner talk stray from religion.
"He said he didn't want to go to Iraq or Afghanistan," said Reasoner, who was raised as a Catholic. "He didn't want to be deployed. He said Muslims shouldn't be in the U.S. military, because obviously Muslims shouldn't kill Muslims. He told me not to join the Army."
And around 1:30 p.m. the next day, authorities say, Hasan, a 39-year-old military psychiatrist, went on the shooting rampage at Ft. Hood that left 13 people dead and at least 38 wounded. Hasan was shot by two civilian police officers and remains hospitalized in stable condition with multiple gunshot wounds.
On Friday, agents were trying to find a motivation for the attack, retracing the suspect's steps in the last days and months, interviewing colleagues, neighbors, friends and family to glean details about Hasan's life -- and whether he was moved, at least in part, by radical Islamic ideology.
But officials also warned the public against drawing conclusions about the attack until more facts are known. President Obama said as much at the White House, as did Army Chief of Staff Gen. George W. Casey Jr. at Ft. Hood.
Much of the furious hunt for answers Friday occurred behind closed doors, as FBI cyber-agents and other forensic experts scoured Hasan's computer, his home and even his garbage.
FBI officials would not say whether they had definitively confirmed that Hasan was the same "NidalHasan" who in one Internet posting -- a comment to an essay titled "Martyrdom in Islam Versus Suicide Bombing!"-- likened a suicide bomber to a soldier who jumps on a grenade to save the lives of his fellow officers in that both were sacrificing their lives "for a more noble cause."
But there were indications that Hasan was active on the Internet and that he had posted numerous inflammatory comments.
By all accounts, Hasan was devout. He worshiped at the mosque each day at 6 a.m., and often prayed there five times a day, especially during the holy month of Ramadan. Hasan's devotion sometimes put him in conflict with the military.
In 2007, Hasan went to the Uniformed Services University of the Health Sciences in Bethesda, Md., for a disaster and military psychiatry fellowship, part of a master of public health degree that he completed this summer.
He was put on probation early in his postgraduate work, however, for allegedly proselytizing about his Muslim faith with patients and colleagues, NPR reported. The university would not confirm the probation, citing the ongoing military investigation.
One of Hasan's classmates in the program said he doubted the man's commitment to the military.
"He told students, 'I'm a Muslim first and an American second,' " Dr. Val Finnell, now a lieutenant colonel at the Los Angeles Air Force Base, said in a telephone interview. "I really questioned his loyalty."
Finnell said he first became suspicious of Hasan shortly after the program began when Hasan gave a provocative presentation in an environmental health class.
Other students focused on topics including mold and water contamination. Hasan's project asked "whether the war on terror is a war against Islam," Finnell said.
"It was very off-topic," Finnell said. "I raised my hand and said, 'What does this have to do with environmental health?' "
Finnell said Hasan became agitated when he was challenged and became "sweaty and nervous and emotional."
Finnell said he and his classmates never brought up Hasan's faith and never asked him about his views of the wars in Iraq and Afghanistan.
"If those topics came up in conversation, it was because he brought those things up," Finnell said. "It was a self-fulfilling prophesy. He made himself a lightning rod by making his extreme views known to everyone."
Hasan, who was born in Virginia and had long worked in the region, moved to Texas in July. It wasn't always an easy fit.
Victor Benjamin, 30, a business student at Central Texas College, also spoke to Hasan after prayers on Wednesday. They talked about Hasan's struggle to find a woman to marry in the Islamic community here, which comprises only a few hundred people. "He told me he was praying to God for guidance," Benjamin said.
In Maryland, Hasan prayed two or three times a week at the Muslim Community Center in Silver Spring, sometimes coming in uniform from nearby Walter Reed Army Medical Center.
"He didn't give an impression that he was a fanatic or angry," said Dr. Asif Qadri, an internist and cardiologist who directs the community center's medical clinic.
"He was very pleasant; he had a smile on his face," agreed Mona Ayad, an administrative assistant. "Always calm and peaceful. . . . That is not the person you would think would resort to this activity. It must have been personal problems."
Akhtar Khan, 64, a member of the center for 25 years, said Hasan would sit in a corner and read books about his faith, sometimes listening to lectures and, "once in a blue moon," attending a social function.
"He was not a real talkative person, but not a loner either," Khan said, describing Hasan as soft-spoken and unimposing. "You knew when you talked to him that you were talking to an educated person."
Like everyone at the center, Khan is mystified by what happened. "What made him do that?" Khan asked. "Were people making fun of him or fun of Islam? Because whatever people do, there is some kind of a reason behind it."
Noel Hasan, the suspect's aunt, said he had suffered name-calling and harassment about his religion after the terrorist attacks of Sept. 11, 2001, and had tried unsuccessfully for several years to win a discharge from the military.
And at Ft. Hood, a community accustomed to death far away -- not here, not of their own -- other acquaintances of Hasan struggled to understand what happened.
"We're better than this," said Sgt. Fahad Kamal, 26, an Army combat medic who wore his fatigues to Friday afternoon prayers at the mosque, and who worked near Hasan at Ft. Hood. "It's not because he was Muslim. It's because of his mental problems."
Josh Meyer of the Washington bureau and Times staff writer Kate Linthicum in Los Angeles contributed to this report.