KILLEEN, Texas—It was still dark on Thursday when Maj. Nidal Malik Hasan left his aging apartment complex to attend 6 a.m. prayers at the brick mosque near Fort Hood. Afterward, he said goodbye to his friends there and asked forgiveness from one man for any past offenses.

“;I'm going traveling,”; he told a fellow worshiper, giving him a hug. “;I won't be here tomorrow.”;

Six hours later, Hasan walked into a processing center at Fort Hood where soldiers get medical attention before being sent overseas. At first, he sat quietly at an empty table, said two congressmen briefed on the investigation.

Then, witnesses say, he bowed his head for several seconds, as if praying, stood up and drew a high-powered pistol. “;Allahu akbar,”; he said—“;God is great.”; And he opened fire. Within minutes he had killed 13 people.

But family members and acquaintances say Hasan's rampage had been building for a long time. Investigators say he bought the gun used in the massacre last July, days after arriving at Fort Hood.

In recent years, he had grown more and more vocal about his opposition to the war and tortured over his role as a Muslim. He tried to get out of the Army, relatives said, and apparently believed it to be impossible, though experts say he was probably given bad advice.

At times, he complained, too, about harassment, once describing how someone had put a diaper in his car, saying, “;That's your headdress.”; In another case cited by relatives, someone had drawn a camel on his car and written under it, “;Camel jockey, get out!”;

Hasan's behavior in the months and weeks leading up to the shooting bespeaks a troubled man full of contradictions. He lived frugally in a run-down apartment, yet made a good salary and spent more than $1,100 on the pistol he used in the shootings.

He was described as gentle and kindly by many neighbors, quick with a smile or hello, yet he complained bitterly to people at his mosque about the oppression of Muslims in the Army. He had few friends, and even the men he interacted with at the mosque saw him as a strange figure whom they never fully accepted into their circle.

“;He was upset,”; said Duane Reasoner Jr., an 18-year-old who attended the mosque and ate frequently with Hasan at the Golden Corral restaurant. “;He didn't want to go to Afghanistan.”;

Hasan was born in Arlington, Va., on Sept. 8. 1970. His parents, Palestinians who had immigrated from the West Bank in the 1960s, moved the family to Roanoke when he was an adolescent. The lower cost of living offered a chance to open businesses, relatives said: first a somewhat seedy bar in the old farmer's market downtown; later a more upscale Middle Eastern restaurant and a convenience store.

Hasan was the oldest of three boys, all of whom helped in the family businesses before going off to college and professional schools. Hasan graduated with honors from Virginia Tech in biochemistry in 1995. His brother Anas became a lawyer and moved several years ago to Ramallah in the West Bank, where the family still owns property, relatives said. The third brother, Eyad, graduated from George Mason University and became a human resources officer for a medical research firm based in Virginia.

Against the wishes of his parents, relatives said, Hasan enlisted in the Army after graduating from college and entered an officer basic training program at Fort Sam Houston, Texas. He was commissioned in 1997 and went to medical school at the Uniformed Services University of Health Sciences in Bethesda, Md., a highly selective and tuition-free program.

After graduating in 2003, he did his internship and residency in psychiatry at Walter Reed Army Medical Center and then completed a two-year fellowship in preventive and disaster psychiatry, earning a masters in public health.

An uncle who lives in Ramallah said Hasan chose psychiatry over surgery after fainting while observing childbirth during his medical training. The uncle, Rafiq Hamad, described Hasan as a gentle, quiet, deeply sensitive man who once owned a bird that he fed by placing it in his mouth and allowing it to eat masticated food.

When the bird died, Hamad said, Hasan “;mourned for two or three months, dug a grave for it, and visited it.”;

Around 2004, Hasan started feeling disgruntled about the Army, relatives said. He described anti-Muslim harassment and sought legal advice, possibly from an Army lawyer, about getting a discharge.

But because he owed the Army money for his education, and probably because the Army was in great need of mental health professionals and was trying to recruit Arab-Americans, he was advised that his chances of getting out were minuscule, relatives said.

“;They told him that he would be allowed out only if Rumsfeld himself OK'd it,”; said a cousin, Nader Hasan, referring to Donald H. Rumsfeld, then the secretary of defense. Relatives said they were unclear whether Hasan sought assistance from a private lawyer; then, about two years ago, his cousin Nader Hasan said, he resigned himself to staying in the Army through the end of his commitment.

An Army spokesman said on Sunday that he did not know the length of Hasan's commitment. But for medical officers, it is typically seven years after graduation from military medical school, which would have meant at least into 2010 for Hasan.

Private lawyers who represent soldiers said it is a difficult but not impossible task to obtain an early discharge from the Army.

A TURN TOWARD ISLAM

During his years in Washington, Hasan turned increasingly toward Islam, relatives and classmates said. In part, he was seeking solace after the death of his parents, in 1998 and 2001.

Hamad, the uncle, said Hasan took the death of his parents hard, isolating himself and delving into books on Islam rather than socializing. “;But this was a few years ago, and I thought he had coped with it,”; Hamad said.

Hasan also seemed to believe that his mosques could help him find a wife, preferably one of Arab descent, he told imams. Faizul Khan, the former imam at the Muslim Community Center in Silver Spring, Md., said he knew women who had been interested in Hasan because he had a good job. But none seemed pious enough, the imam said.

Though Hasan told his cousins that he planned to marry sometime this year, he was not known to have ever had a girlfriend, relatives said.

During his time at Walter Reed and the Uniformed Services University, Hasan also became increasingly vocal in his opposition to the war. He knew much about the harsh realities of combat from having counseled returning soldiers, and was deeply concerned about having to deploy. But over the past five years, he also began openly opposing the wars in Iraq and Afghanistan on religious grounds.

A former classmate in the master's degree program said Hasan gave a PowerPoint presentation about a year ago in an environmental health seminar titled, “;Why the War on Terror Is a War on Islam.”; He did not socialize with his classmates, other than to argue in the hallways on why the wars were wrong.

The former classmate, who spoke on condition of anonymity because of working for the military and not being authorized to speak, said some students complained to their professors about Hasan, but that no action had been taken. “;It didn't cross my mind that he was dangerous,”; the former classmate said. “;He's a chubby, bald guy. He wasn't threatening.”;

But Dr. Aaron Haney, who was a year ahead of Hasan in the residency program, said there were many people at Walter Reed who expressed opposition to the war. He also said he had witnessed anti-Muslim or anti-Arab sentiments expressed by soldiers at Fort Campbell, Ky., where Haney trained before he deployed.

One of Hasan's supervisors, Dr. Thomas Grieger, said that Hasan had difficulties while at Walter Reed that required counseling. But Grieger said on CNN that Hasan “;responded to the supervision that he received.”;

“;He swore an oath of loyalty to the military,”; Grieger told The Associated Press. “;I didn't hear anything contrary to those oaths.”;

A person who is familiar with the residency program at Walter Reed said that it is not unusual for residents in the psychiatry program to be sent for counseling at some point. The person said that the fact that Hasan had completed his residency in good standing and was accepted into the fellowship was in itself an indicator that nothing he did signaled major problems.

In May, after completing the fellowship, he was promoted to major and two months later, he was transferred to Fort Hood, the Army's largest post. When he arrived there on July 15, his deepest fear—deployment to Iraq or Afghanistan—seemed almost certain.

A FORT HOOD ASSIGNMENT

In late July, Hasan moved into a second-floor apartment in a rundown building on the north side of Killeen, paying $2,050 for his six-month lease up front, the apartment manager, Alice Thompson, said. The two-story faded brick complex, Casa Del Norte Apartments, has an open courtyard with exterior stairs and advertises move-in specials.

A few days later, Hasan bought an FN Herstal 5.7-millimeter pistol at a popular weapons store called Guns Galore, just off the highway that runs between the mosque that Hasan attended and the base, federal law enforcement officials said.

The tenants generally saw him leave early and come home late in the afternoon, usually in his fatigues. He never had visitors, they said, but he was friendly with his neighbors.

“;The first day he moved in, he offered to give me a ride to work,”; said Willie Bell, 51, who lives next door to Hasan. “;He'd give you the shoes and shirt and pants off him if you need it. Nicest guy you'd want to meet.

“;The very first day I seen him, he hugged me like, 'My brother, how you doing?' “;

In mid-August, another tenant, a soldier who had served in Iraq, was angered by a bumper sticker on Hasan's car proclaiming “;Allah is Love”; and ran his key the length of Hasan's car. Thompson told Hasan about it that night, and though he called the police, Hasan did not appear to be angered by it. “;If he was angry, I didn't know,”; Thompson said.

On the base, Hasan was assigned to the pychiatric wards at the Carl R. Darnall Army Medical Center, military officials said. Col. John Rossi, deputy commander of Fort Hood, said Hasan's function on base was “;assessment of soldiers before deployment.”;

In early September, he also began worshiping at the Islamic Community of Greater Killeen mosque, on the southern outskirts of town, which about 75 families attend. He prayed their as often as five times a day, kneeling in a plain room with bright green carpet.

But he was still wrestling with his role as a Muslim. He invited Osman Danquah, the co-founder of the mosque, to dinner at Ryan's restaurant and asked him how he should counsel young Muslim soldiers who might have objections to the wars. Danquah, a retired sergeant and veteran, told him the soldiers had no excuse since it was a volunteer army and they could always file as conscientious objectors.

“;I got the impression he was trying to validate how he was dealing with it,”; Danquah said.

Hasan also applied to become a lay Muslim chaplain on the army post, according to an army chaplain, who requested anonymity.

'PRAY FOR ME'

Then in late October, Hasan told the imam, Syed Ahmed Ali, that he was leaving Texas for Virginia to live with his family there. “;He said, 'Pray for me,' “; Ali said.

But he never left. The night before the shooting, he had dinner with Reasoner and said he felt he should not go to Afghanistan.

“;He felt he was supposed to quit,”; Reasoner said. “;In the Quran, it says you are not supposed to have alliances with Jews or Christians, and if you are killed in the military fighting against Muslims, you will go to hell.”;

Hasan began shooting at about 1:20 p.m., investigators say.

As he methodically moved around the room, he spared some people while firing on others several times. He seemed to discriminate in his targets, though it is unclear why he seemed to choose some and not others. All but one of the dead were soldiers.

“;Our witnesses said he made eye contact with a guy and then moved to somebody in uniform,”; Rep. Mike. Conaway of Texas said.

He fired more than 100 rounds.

The intermittent firing gave some soldiers false hope as they hunkered down in the processing center, flattening themselves under tables and propping chairs against flimsy cubicle doors.

Pfc. Marquest Smith, 21, said that in the midst of the rampage when the bursts would end, and the center would go quiet for a few seconds, people thought Hasan was out of rounds, prompting some to escape, or at least peer over cubicle walls, only to hear the popping again.

Witnesses said the floor became drenched with blood and that soldiers, apparently dead, were draped over the chairs in the waiting area or lying in the floor.

Spc. Matthew Cooke, 30, who was expecting orders to leave for Afghanistan in January, was waiting on line to be processed in the medical building when Hasan opened fire. A solider standing near him was hit, crumpling to the ground in an instant, and Cook dropped to his knees and leaned over the wounded soldier to shield him from being struck again, Cooke's father, Carl, said in an interview.

Hasan walked up to Cooke, who had returned from a 15-month tour in Iraq earlier this year, his gun pointed down at his back and shot him several times at point blank. “;The rounds nicked his colon and several places in his intestines, bladder and spleen,”; his father said.

Cpl. Nathan Hewitt, 27, thought that he was in the midst of an unannounced training exercise when he heard the gunfire erupt. Then he saw the blood on his thigh and felt the sting from the bullet that had just hit him, according to his father, Steven Hewitt.

Then, the shooting stopped momentarily, and Hewitt started to crawl out of the room on his belly with the others following. Hasan was only reloading. He started to shoot again, hitting Hewitt again in the calf.

Some cars parked outside of the processing center even had bullet holes in them. The first police to arrive on the scene found Hasan chasing a wounded soldier down outside the building, investigators said. Pulling up in a squad car, Sgt. Kimberly D. Munley went after him and shot him down in an exchange of gunfire that left her wounded.

It was 1:27 p.m.