BAGHDAD — U.S. soldiers fanned out with search dogs and shovels after getting a series of tips.

As dusk fell hours later, they found the remains of Staff Sgt. Keith Matthew Maupin in a dangerous swath of desert on Baghdad’s northwestern outskirts — about 12 miles from where he was captured in an ambush nearly four years ago.

The March 20 discovery was a mixed blessing for the troops of the 1st Battalion, 21st Stryker Infantry Regiment.

“To find out that we were able to recover one of our fallen comrades and bring him home to his family is really an indescribable feeling,” said Capt. Jeff Higgins, the commander of the Bravo Company that found the remains. “I’m sure it took some hope away from the family, but I think it probably gives them some much-needed closure.”

It was the second search for Maupin in Abu Ghraib in two months as the U.S. military received an increasing number of tips from new Sunni allies, including former insurgents, who have joined forces against al-Qaida in Iraq.

U.S. commanders said the find came from a combination of piecing together years of information and new tips, luck and “a lot of painstaking walking.”

The Army used DNA testing to identify the remains and said the discovery of a shirt helped in the search. But commanders declined to provide more details about the items found out of respect for the family.

An official with the local awakening council, as the U.S.-allied Sunni groups are called, said U.S. soldiers had spent the past year driving through the area with loudspeakers offering a $200,000 reward for information on Maupin’s body.

The search appeared to intensify about a month ago, focusing on sparsely populated areas near the highway linking Baghdad with the former insurgent stronghold of Fallujah to the west, according to the official, who spoke on condition of anonymity because of security concerns.

He said many witnesses had reported seeing bones and U.S. military clothes near the highway.

Lt. Col. Mario Diaz, the battalion commander, declined to comment on reward money or point to a specific piece of information that led to the remains.

“We were narrowing it down, and it got to the point where we had the right people, the right information and the right location and we were close enough to take advantage of it,” he said.

The April 9, 2004, capture of Maupin, a 20-year-old private first class from Batavia, Ohio, was one of the most brazen attacks against U.S. forces as the Sunni-led insurgency staged a series of kidnappings and videotaped beheadings.

Diaz, who took over the battlespace comprising the volatile area of Abu Ghraib on Jan. 13, said the discovery of the remains showed how times have changed, aided by a Sunni alliance that has been a key factor in a sharp decline in violence nationwide.

“It is a step in the right direction,” he said.

Diaz’s first try at finding Maupin in a different spot in late January failed — as so many had before it — and he was prepared for the March effort to do the same. The operations were dubbed Trojan Honor I and II after Maupin’s high school mascot.

Abu Ghraib is a predominantly Sunni farming district that sits on the edge of Anbar province and has been one of the hardest areas to control since the 2003 U.S.-led invasion. It also is the site of a prison that became notorious when U.S. troops were caught abusing inmates there.

Diaz, 40, of Pasadena, Calif., said Abu Ghraib remains dangerous. Troops in the area faced small-arms fire in the 72 hours leading up to the search.

Soldiers using shovels, small-hand tools and search dogs combed for hours through the area, which is lined with dirt roads and canals but not much else, Diaz said.

Daylight was waning when the soldiers found Maupin’s remains and personal effects.

Maupin disappeared after his fuel convoy, part of the Bartonville, Ill.-based 724th Transportation Company, was ambushed west of Baghdad — a year to the day after invading U.S. forces entered Baghdad, officially marking the ouster of Saddam Hussein.

A week later, the Arab television network Al-Jazeera aired a videotape showing Maupin sitting on the floor surrounded by five masked men holding automatic rifles.

That June, Al-Jazeera aired another tape purporting to show a U.S. soldier being shot. But the dark and grainy tape showed only the back of the victim’s head and not the actual shooting, and the Army ruled it was inconclusive.

Diaz said it was satisfying to be leading the unit that found Maupin.

“We knew that we were providing closure to a family,” he said. “We were completing our mission of never leaving a fallen comrade behind.”