"He would have understood what happened," said Lisa Marie Donato, a 1998 Palm Springs High School graduate who now lives in the Los Angeles area. "He would be the first one to say, `It's OK, guys.' "

Prosser, 28, who celebrated last Christmas with his mother and stepfather at their Rancho Mirage home in eastern Riverside County, died Wednesday when a bomb missed its Taliban target and landed 100 yards away. The explosion killed two other American soldiers and wounded 20 others in the worst "friendly fire" accident of the war.

His mother, Ingrid Solhaug, was too upset to be interviewed at her Seattle home, where she and Prosser's stepfather, Al, live about half the year.

Prosser, an Army staff sergeant in the Green Berets and member of the special forces, served in the area of intelligence and as a result they knew few details of his work, Al Solhaug said.

"He was the most impressive, most patriotic, nicest guy you could ever meet in your life," Solhaug said. "He was a national hero."

A week before he left for Afghanistan, Prosser told his wife Shawna that he loved her very much, that the war would be costly but would be waged for the good of everyone, Solhaug said.

"He didn't realize it would cost him his life," Solhaug said, but he accepted the risks of a job that included going out on missions to identify the enemy and spot targets.

"The most important thing to him was this country and protecting it," his sister said. "I knew that he would be the first person out there. I was worried about him every day. That's just how he was. He was a brave guy. I'm sad, but I'm really happy that the country is getting to see what a good man he was."

Prosser was captain of his Maricopa High School football team near Bakersfield and was a "big brother" to many people, Donato said. He would tell her and his other brothers the importance of good grades, staying in school and going to college, she said. When he visited the desert, he would sit with her friends and tell them about the Army. "He loved his job, he loved the Army."

And he wouldn't blame anyone for his death, Donato said.

"Nor do we," she said. "It was a mistake and mistakes happen. Knowing him, he'd be over here telling us that it wasn't anyone's fault, that he died noble."

Prosser had been stationed at Fort Campbell, Ky. The family plans to return there today for a planned service on Monday. Another service is planned Friday in Bakersfield before Prosser is buried in Arlington National Cemetery, family members said.

The other special forces soldiers killed were Master Sgt. Jefferson Donald Davis, 39, of Watauga, Tenn., and Sgt. 1st Class Daniel Petithory, 32, of Cheshire, Mass. All were stationed at Fort Campbell.

Associated Press contributed to this report.