FORWARD OPERATING BASE CALDWELL, Iraq — Black Hawk helicopters arrived in unusual numbers at this remote base in Diyala province on Wednesday, carrying senior officers and NCOs to a memorial service for an interpreter and three soldiers, including a troop commander, killed by a roadside bomb on March 10.

Hours earlier, a helicopter had lifted off in the opposite direction, ferrying away the body of another soldier.

That soldier, who is not being identified pending notification of his family, died in a vehicle rollover Wednesday morning, officers said, lending a fresh lining of grief to an already heavily laden day.

“I don’t think I’ve ever done a ‘Heroes Flight’ and a memorial in the same day,” said Capt. Ben Ellington, the chaplain for 2nd Squadron, 3rd Armored Cavalry Regiment.

Though the new loss loomed over the day, attention remained focused on the men killed near the village of Balad Ruz just over a week earlier. They were Capt. Torre Mallard, the squadron’s F Troop commander; Sgt. Phillip Anderson, his gunner; and Spc. Donald Burkett, his driver. Albert Haroutounian, an Armenian-American who had served as Mallard’s interpreter, was also killed, and another soldier was injured in the blast.

A 2002 West Point graduate, Mallard, 27, of Anniston, Ala., was remembered for a quick sense of humor and a broad willingness to engage enlisted troops.

Pfc. Ryan Vickers remembered the first time he met Mallard, when the captain took command of the Troop, based at Fort Hood, Texas.

“Here I was a PV2 — basically a nobody — and he took time on his day to come talk to me and my mom and her boyfriend,” he said.

“He made it fun to be a soldier,” Vickers said. “It sounds stupid, but he was willing to listen to us and take from our experiences, and that made it fun.”

Lt. Col. Paul Calvert, the squadron’s commander, described Mallard as a “tremendous leader who simply loved being a soldier.”

Mallard left a wife, Bonita, and two sons, Torre Jr. and Joshua. Anderson, 29, of Mexico, Mo., is survived by his wife, Melanie, and son, Warner. Burkett, 24, of Brownwood, Texas, left a wife, Brandi, and son, Mason.

All three were posthumously awarded Bronze Stars and Purple Hearts. Anderson had been previously awarded a Purple Heart, and Mallard had won a prior Bronze Star, the Army said.

Anderson, who had trained as a tanker, took pride in his skills as a gunner and enjoyed “talking smack” to other gunners and the cavalry scouts, said Sgt. Montgomery Adams, who had served with Anderson for six years.

“Thanks for always being there when I needed you,” Adams said.

Burkett was “known for his goofy smile and his positive attitude,” said Pfc. Anthony Wix-Aguilera.

“Heading to deployment, you wouldn’t find him in the bars or clubs,” Wix-Aguilera said. “You’d find him in his newly purchased home with his family.”

Haroutounian, 36, was born in Kuwait and attended an Armenian private school where he learned Arabic and English. He immigrated to the U.S. at age 14 and lived in Philadelphia before signing up to work as an interpreter. Haroutounian had written several children’s books and was saving money to open a pizzeria, colleagues said.

“He loved talking to soldiers, taking pictures like a tourist and telling stories,” F Troop First Sgt. Zeneido Gonzalez said.

After a procession of generals, colonels and sergeants major had paid their respects, the men of F Troop came forward to kneel before the simple memorial — three rifles turned downward, crowned with helmets and hung with dog tags, and three pairs of boots.

The service was the troop’s first pause since the four were killed, and soldiers said they were glad for the continued work. Capt. Trey Smith, who had taken command of the Troop after Mallard’s death, had served with Mallard as a staff officer and attended several military schools with him.

“It’s been intense,” he said. “But in a sense, I think the fact that we were friends has made it a little easier for me to come in here.”

During a patrol of a dusty village near the Iranian border on Tuesday, Smith had gone off with a local sheik to inspect an unfinished medical clinic while other soldiers took retinal scans and fingerprints from village men.

Though commanders say security has improved here in recent months, Diyala remains among the most dangerous parts of Iraq.

“For a lot of us, having this happen has added to our motivation,” Vickers, 20, of Madison, Ohio, said. “It’s a cliche, but you just drive on. It is what it is.”