Reporting for a story on Vietnamese MIAs took me one Sunday afternoon to a municipal building in Northern Virginia, where a veterans group had gathered.

Kevin Cao, 16, learned of his missing great-uncle only through a chance encounter with others looking for MIAs. (Matt McClain/For The Washington Post)

Kevin Cao, a junior at Thomas Jefferson High School for Science and Technology, happened to be in the building. Cao was there to meet with parents who wanted to sign their children up for a free tutoring program that he’d created for area elementary school students.

As Cao, 16, waited for parents to trickle in, he noticed the older men being interviewed and photographed. He asked what was going on. McClain and I explained that we were doing a story about Vietnamese in the area who had loved ones still missing from the war.

Cao was born in the United States, but his parents and grandparents hailed from Vietnam. He wasn’t sure if he had any MIAs in his family. So on the spot, he phoned his father.

Turns out that Kevin Cao had a great-uncle, Thanh Cao, who fought for the South and disappeared in battle in 1972. Thanh Cao was his grandfather’s brother. He was a favorite, playful uncle to his father.

Cao’s father and grandfather still pray that Thanh’s remains will be recovered. Thanh’s sister has performed ceremonies on behalf of his soul, which some Buddhists believe cannot go to heaven until the body gets a proper burial.

But as much as the pain of the war lives on for the older Caos, they have chosen to share little of it with the generation born here.

“Why hasn’t anyone ever told me about him?” Kevin asked his father.

When the call was over, Kevin relayed his father’s reply: “He told me, ‘The Vietnam war was long — and over.’”