FORT HOOD, Texas — As federal investigators continued to figure out how and why an Army psychiatrist went on a deadly rampage Thursday, the families of the victims were thinking of more personal matters.

The authorities say that a gunman, whom they identified as Maj. Nidal Malik Hasan, 39, fired more than 100 bullets inside Fort Hood's medical processing building on Thursday, killing 13 people and wounding 30 others. How he was able to execute such a deadly act — and why — has become the focus of federal investigators.

"We can't answer those questions, but we're not focusing on that," said Keely Vanacker, 33.

"Right now, we're thinking how is the best way we can memorialize my father," she said of Michael G. Cahill, 62, a retired National Guardsman. The major had been scheduled to be deployed to Afghanistan along with other mental health professionals.

Five of the 13 people who died in the shooting were from medical units. Three were members of the 467th Combat Stress Control Detachment, of Madison, Wis.

Capt. Russell Seager, 41, of Racine, Wis., was a nurse practitioner who helped veterans struggling with post-traumatic stress disorder, at the Clement J. Zablocki Veterans Affairs Medical Center in Milwaukee. He also taught at Bryant and Stratton College in Milwaukee and was pursuing a Ph.D. in education.

"He just wanted to help the soldiers because they helped us," his uncle Larry Seager, of Mauston, said in a telephone interview. "And then he got shot by a psychiatrist."

Maj. L. Eduardo Caraveo, 52, of Woodbridge, Va., who was a licensed clinical psychologist, was in Seager's unit.

Caraveo's son Eduardo told the Arizona Daily Star that his father had moved from Mexico to the United States in the 1970s and was the first in his family to go to college. He earned a doctorate in psychology at the University of Arizona, had taught bilingual special-needs students and also had worked with Child Protective Services in Arizona.

Recently in Virginia, Caraveo served as a marriage counselor, and his website said he "specializes in the areas of Marital Counseling, Positive Thinking, Military Families Pre-post Deployment Issues, and Diversity Training."

Sgt. Amy Krueger, 29, of Kiel, Wis., joined the Army shortly after the Sept. 11, 2001, attacks. She "was a feisty young lady who wouldn't back down from anything," said Faye Billmann, a teacher at Krueger's old high school in Kiel who is organizing the school's annual Veterans Day ceremony. There will be a moment of silence Wednesday, Billmann said, in Krueger's honor.

Two members of the 1908th medical detachment out of Topeka, Kan., were also confirmed dead in the attack: Capt. John Gaffaney, 56, of Serra Mesa, Calif., and Lt. Col. Juanita Warman, 55, raised in Pittsburgh and living in Independence, Mo.

Gaffaney, who had worked with mentally disabled adults in San Diego, had also been deployed as part of a reserve combat stress unit.

Warman joined the military like her father and grandfather, her sister Margaret Yaggie said in a telephone interview. Warman was a physician's assistant who was also a member of one of the Army medical reserve units.

In all, 85 members of three combat stress units — from Madison, Wis.; Topeka, Kan.; and Durham, N.C. — were on the base at the time of the attack, said Maj. Claudia Jefferson, an Army Reserve Command public affairs officer.

Cahill, the 62-year-old retired National Guardsman, spoke to soldiers all the time in his job as physician's assistant, taking their histories and listening to their stories. In the times when he met soldiers who were too unstable to walk to psychiatric services, Cahill would walk them there himself.

"He always made sure they got the best care they needed," his daughter Keely Cahill Vanacker said Saturday from her father's house in Cameron, Texas, where her family was in mourning.

There were others inside the Soldiers Readiness Processing Center, men and women from all over the country, who had no connection to the mental health services. They were standing in the various lines that were notorious inside the center.

Staff Sgt. Justin M. DeCrow, 32, of Evans, Ga., was training soldiers on how to help veterans in processing paperwork, according to The Associated Press. He leaves behind a wife and a 13-year-old daughter.

Pfc. Michael Pearson, 21, of Bolingbrook, Ill., joined the Army a year ago, was training to deactivate bombs and was known for his nimble fingers on his Fender Stratocaster guitar.

Spc. Jason D. Hunt, 22, joined the military three years ago because, he told his grandmother, in Frederick, Okla., "it was time to grow up." And when his two-year commitment was finished, he re-enlisted for six more years, right in the middle of the Iraq desert on his 21st birthday.

"It says a lot about a man who chooses to do that in the middle of the war," his sister Leila Willingham said Friday.

Hunt was on his way back to join his division in Iraq, waiting to get inoculations when he was shot. Willingham, 30, could not help recalling a conversation she and her younger brother had recently had. His wife, Jennifer Hunt, had three children from a previous marriage. Willingham has two children, whom she said her brother also adored.

"We were discussing the love of a parent, and he said: 'I would die for your children. I would die for a stranger. And I would jump in front of a bullet for another soldier,'" she recalled.

Willingham said that her family had been told around midnight Thursday that her brother had died but that they were still waiting for information on how. "I don't know the details, but I know my brother," she said. "And he wouldn't run from something like that."

All 13 victims' bodies were taken to Dover, Del., for autopsies.

Spc. Frederick Greene, 29, of Mountain City, Tenn., was among them. Greene was a member of the 16th Signal Company at Fort Hood.

For some soldiers, military service ran in the family.

Francheska Velez, 21, of Chicago, was returning home from Iraq because she was in the first trimester of her pregnancy. Called Checka by her friends, who had described her as "always happy," Velez had joined the Army three years ago to fulfill her father's dream of serving the country.

"She knew I always wanted to be in the Army," her father, Juan, a Colombian citizen, said in Spanish. He learned Thursday of her death. "I didn't expect it to happen here and not in Iraq. The worst thing was, it wasn't a terrorist. It was an American soldier."

Pfc. Kham Xiong, 23, was simply in line for a physical at the center and was responding to a text message from his wife, urging him to come home for lunch. Right before the shots rang out, he responded that it was almost his turn to be seen by doctors, his relatives told KSTP-TV in Minnesota. Xiong, who has three young children, had moved his family to Texas while he prepared to deploy overseas.

Pfc. Aaron T. Nemelka, 19, of West Jordan, Utah, was preparing for a new life as well. He had been planning to propose to his girlfriend next month before deploying to Iraq or Afghanistan in January, relatives told the Salt Lake Tribune and the Deseret News. They said Nemelka, an Eagle Scout, had been training to dispose of munitions.

"I miss everything about him," his grandfather Michael Nemelka told reporters outside his house, where neighbors had planted American flags.