The grave of U.S. Army Capt. Humayun Khan at Arlington National Cemetery in Arlington, Va. (Mark Wilson/Getty Images)

Capt. Humayun Khan didn’t need to be out there that day.

Not all officers at Forward Operating Base Warhorse would choose to spend that kind of time outside the gates of their fortified compound, checking on lower-ranking soldiers pulling security detail, said Marie Legros, a staff sergeant posted at the facility in eastern Iraq in 2004. 

But Khan, a Army reserve officer and naturalized American on his first deployment to Iraq, was a hands-on supervisor who wanted to know what was going on with the men and women under his command. It was early summer 2004, and conditions in Iraq — including in the restive eastern province of Diyala — were growing more dangerous by the day.

Army Capt. Humayun Khan was killed June 8, 2004, after a vehicle packed with explosives drove to the gate of his compound while he was inspecting soldiers on guard duty near Baqubah, Iraq. (Family photo)

“That’s the thing,” Legros said. “He went just to check on his troops.”

What’s more, June 8 was Khan’s day off, said Crystal Selby, a sergeant at the time who, like Khan, worked the midnight-to-noon force protection shift. Selby said she had tried to convince the 27-year-old captain that he needed his rest, but he was adamant that she drive him to the base’s gate so he could see how the guard personnel were doing.

“I dropped him off there, and it wasn’t five minutes after that it happened,” Selby said in a phone interview, her voice choked with emotion.

Khan was standing with other troops outside Warhorse that morning when an orange taxi came speeding toward them. Instructing his soldiers to get down, Khan moved toward the vehicle, motioning for it to stop. Before he could reach the car, an improvised bomb went off, killing Khan and two Iraqi civilians in addition to the two suicide bombers. A dozen more people were wounded.

For fellow members of the 1st Infantry Division’s 201st Forward Support Battalion, the loss of an officer who, according to  his comrades, was universally liked and respected was a devastating moment relatively early in their deployment in Iraq.

“He was just that type of person, wanting to make sure his soldiers were okay,” Legros said. He was a “soldier’s officer,” she said, personally invested in those serving under him.

Following his father’s emotionally charged speech at last week’s Democratic convention, Khan is now at the center of a major political controversy about the role of Muslims in America and the treatment of families who have lost loved ones in the line of duty.

Soldiers who served with Khan declined to talk about the political dynamics swirling around his family’s public stand. But they described the captain as a down-to-earth young officer who set aside the conventions of military hierarchy to connect with lower-ranking soldiers and enlisted personnel.

“He never put his rank above his care for his soldiers and his comrades,” said Laci Walker, who was a sergeant and worked in a motor pool at Warhorse under Khan’s supervision. Walker’s memories of Khan in Iraq are rooted in his generosity and interest in others: Khan pulling out an extra towel to lend Walker when she forgot hers; Khan, who had a habit of making himself tuna fish sandwiches, letting others know that the condiments in his drawer were up for grabs to all.

Even 12 years later, Walker said her feelings were too raw to talk about the aftermath of Khan’s death. “He was the most amazing officer I ever worked for,” she said.

It wasn’t immediately obvious that Khan, who was born in the United Arab Emirates in 1976, was bound for life in the U.S. military.

Khan’s parents arrived in the United States when Khan was 2 years old. He graduated from Kennedy High School in Silver Spring, Md., in 1996 and earned a degree in psychology from the University of Virginia in 2000. He planned to be a lawyer, said his father, Khizr Khan, who is an attorney.

But in Charlottesville, Khan made friends with students who were part of the university’s ROTC program, and the idea of military service appealed to him, said Nizam Missaghi, a classmate of Khan’s older brother who got to know the younger Khan at the University of Virginia. According to Khan’s family, he had learned about Thomas Jefferson as a boy and was inspired by the idea of safeguarding freedom.

“He liked the discipline and the opportunity to serve, and so he chose that path,” Missaghi said. “He was very loyal to his choice.”

Those who knew and worked with Khan said his South Asian heritage — his parents were born in Pakistan — and his Muslim faith weren’t a secret, but neither were they something he wore on his sleeve. Missaghi described Khan as “just your average, all-American kid” who had an infectious sense of humor and a knack for connecting with others.

“If he entered a crowd and someone seemed to be marginalized … he would be the first person to reach out to them,” Missaghi said.

In his short time in Iraq, Khan had worked on a program to provide employment to Iraqis and tried to involve tribal leaders, former colleagues said. By phone and in online tributes, those who served with Khan described the lasting impression he made on them. “June 8th every year is a very sore spot with me,” Selby said.

Brig. Gen. Dan Mitchell, who as a lieutenant colonel was Khan’s commanding officer in 2004, said that as a force protection operations officer at Warhorse, Khan was playing a critical role in keeping fellow soldiers safe from artillery attacks, sniper fire and improvised explosive devices like the one that killed him.

In a statement, Mitchell called Khan, who was awarded Bronze Star and Purple Heart medals after his death, an “exceptional person, leader and military officer” who loved his soldiers.

“On the day he died, he was doing exactly what a good leader should do,” Mitchell said.

Julie Tate and Dan Lamothe contributed to this report.