Lance Cpl. Christopher Jenkins Dyer enlisted in the Marines and served in Iraq because he believed in the United States' mission to defend freedom in the fledging democracy, friends and family said.

On Aug. 3, he sacrificed his life for that cause when a roadside bomb detonated near the amphibious assault vehicle he was riding in, south of Haditha. Dyer, 19, was the youngest of 14 Marines killed in the explosion, and one of nine in his Columbus, Ohio-based Lima Company to die in the attack.

He was assigned to the Marine Forces Reserve's 3rd Battalion, 25th Marine Regiment, 4th Marine Division.

"Chris was truly proud to give his life for freedom," longtime family friend Keith Stone of Fairfield, Ohio, wrote in an e-mail to the Washington Post.

Yesterday, about 50 mourners watched as Dyer was laid to rest at Arlington National Cemetery. During the service, Dyer's father, John, wiped his eyes with a handkerchief as the Marine's mother, Kathy, leaned close. Marine Brig. Gen. Doug Stone knelt before the grieving father and presented him with an American flag.

Dyer, who hailed from Evendale, Ohio -- outside Cincinnati -- had been memorialized Wednesday at a service at Tri-County Baptist Church in West Chester, Ohio. A giant American flag was stretched between two fire engines in front of the church as hundreds gathered to mourn the tall, long-legged young man.

"It is obvious that Chris learned from his father at a very early age the value of giving to others," Robyne Magness of Mason, Ohio, who has known the Dyers for nearly a decade, wrote in an e-mail to the Post. "Chris committed his life to a cause and a purpose that was greater than himself. He did at 19 what so many others strive for their entire lives -- to find a cause for which you would give your life."

Jason Rosser, 19, was a classmate of Dyer's from seventh grade through high school. He remembered his friend writing an essay in junior high about wanting to join the military when he grew up; as the years passed, Dyer never let anything interfere with his goal, Rosser said.

"He lived every day to the fullest -- if I was given 100 years more I still couldn't catch up to him," said Rosser, a student at Ohio State University.

Dyer had planned to enroll at Ohio State when he was called up last summer by the Marines, Rosser said. Dyer, who was scheduled to come home this fall, planned to begin classes at the university in January and major in finance, he said.

While serving in Iraq, Dyer remained close to those who had watched him grow up and was grateful for his roots in the community. In the spring, he took the time to write to the second- and third-graders in Keith Stone's Sunday school class to thank them for the letters they had sent him in Iraq -- correspondence he had enjoyed sharing with fellow Marines.

"Chris was a young man who had tremendous drive and tremendous potential," recalled Raymond L. Spicher, principal of Princeton High School in Sharonville, Ohio, from which Dyer graduated last year. He said the school will hold a moment of silence in Dyer's honor at its first home football game this season.

Spicher recalled Dyer's enthusiasm for academics, as a participant in the school's college-level International Baccalaureate program, and athletics, as a champion swimmer and diver. He also played viola in the school's concert band. "He was really intense about a lot of aspects of life but also fun-loving," Spicher said. "He knew how to have a good time."

Dyer was the 170th person killed in Operation Iraqi Freedom to be buried at Arlington.

The American flag is suspended over the remains of Lance Cpl. Christopher Jenkins Dyer during the service at Arlington National Cemetery. Dyer, 19, was killed Aug. 3 in Iraq when a bomb exploded near the vehicle he was in.