LOS ANGELES -- When Bill Vargas got a phone call from a stranger that one of his dog tags had turned up on a street vendor's cart in Ho Chi Minh City, he thought it was some kind of scam.

Vargas had lost the metal identification tag in the jungles of Vietnam during the height of the war in the late 1960s. He figured that it was gone forever.

But the 58-year-old plumbing contractor from Placentia, Calif., overcame his skepticism and agreed to attend a ceremony for veterans in Santa Ana, Calif., where he met Verilyn and Martha Roskam, the Illinois couple who had found his tag.

Looking at the small metal plate he had carried through two combat tours beginning in 1966, Vargas realized he had made the right decision.

''It was an amazing feeling to see it," he said. ''You get kind of choked up, you know. It just reminds me of my time there -- it's hard to talk about, even now."

For the Roskams, Vargas's reaction was further validation of their quest that began four years ago during a business trip to Vietnam, where they bought more than 30 American dog tags from a street merchant for $20 and set about returning each one.

Though arduous, the act of returning the tags, either to the veterans themselves or their surviving family members, has been deeply emotional.

For the recipients, the sight of the tags reawakened memories and, on occasion, helped quiet long-unsettled recollections.

The Roskams were not alone in the effort to connect long-lost tags with their owners or surviving families; they are aware, they say, of several people who have recovered, and in some cases returned, US military dog tags found in Vietnam.

One tourist bought 1,444 tags from Vietnamese shops and street vendors in 1994 and gave them to US investigators still searching for possible prisoners of war, as well as soldiers missing in action and their remains.

The tags were sent to the US government's Joint POW/MIA Accounting Command's Central Identification Laboratory in Hawaii, where investigators conducted what they described as ''some of the most in-depth research" on Vietnam dog tags to date.

In the latest issue of Vietnam, a bimonthly history magazine devoted to the war, three of the researchers detailed their efforts. ''What we have found," they wrote, is ''that the vast majority seem to be genuine." They hope to return the tags to their former owners and families.

The Roskams's quest started during a 2001 trip to Vietnam. Verilyn Roskam, 75, was busy working when his wife decided to go shopping. While browsing at a street vendor's table in Ho Chi Minh City, Martha Roskam recalled, something startling caught her eye: a bunch of US military dog tags displayed atop a wicker basket, and looped neatly on a string.

''I knew right away what they were because my dad was in the First World War, my two brothers were in World War II, and my husband was in the Korean conflict," she said. ''I knew that when people are in combat, their only identification are their dog tags. It made me sad to think that these things were being sold as souvenirs."

After consulting with her husband, Martha returned to the merchant's stand the next day and bought the entire lot for $20. ''We just felt it was a matter of honor," Verilyn Roskam said.

Back home in Wheaton, Ill., they began the painstaking task of authenticating the tags and trying to track down their owners. One of the first people they contacted was their son, state Senator Peter Roskam, Republican of Illinois, who helped put them in touch with government and military officials to verify that the tags were real. Satisfied that they were, the Roskams, aided by a private investigator, began using military and public records to learn as much as they could.

They checked government archives to verify names and serial numbers. They contacted federal officials for last-known addresses, some dating to 1967. And finally, Roskam said, they spent almost two years searching telephone books, property records, and other public forms to find the whereabouts of each serviceman.

David Bayard, a spokesman for the Western regional office of the US Department of Veterans Affairs, said his office had helped to put the Roskams in touch with some of the veterans involved.

''It seemed that the fit was right," he said. ''When he came up with a pair of dog tags and we contacted veterans, they had generally lost them. As far as I know, it seemed to work out -- we believe they are real dog tags."

To date, Roskam says, the couple has returned about a dozen dog tags to veterans or families in eight states. Three of the men, he said, had been killed in Vietnam; a fourth died later of natural causes in the United States.

An additional six veterans, according to Roskam's website at www.roskamdogtag.com, have been located and are awaiting the return of their tags.

And 13 more, he said, are still being sought.

''It's not a fast process," Roskam added.

Yet the men's reactions, he said, have made it worthwhile. Some openly wept while receiving their tags. Many beamed with a sense of postponed pride and relief, describing the experience as the first time they have been recognized for their sacrifices in Vietnam.

And almost everyone, Roskam said, has seen the return of the tags as a miraculous redemption from the past.

Alfred Moreno Jr.'s family believes he was wearing his dog tags the day he was killed by a land mine in South Vietnam.

Among the personal effects they received after the 21-year-old Marine's death in 1969 were a uniform and belt, both blown apart by the explosion. Absent, however, were the identifying pieces of metal stamped with his name, religion, and blood type.

''I never thought about them," said Ann Sandoval, Moreno's aunt, now 68, with whom he had lived before enlisting.

But one day, the Roskams knocked on the front door of her Phoenix home and handed her the intimate memento of her long-dead nephew. ''It brought it all back," she said, ''but with more understanding." The Roskams, too, got caught up in the emotion.

''She and my wife just wept," Verilyn Roskam said. ''They took us out to the cemetery; the majority of his siblings were there and it was a wonderful day with the family. It opened up old wounds, but also brought a closing."

While Vargas didn't recall exactly where he had lost his tags, others remember distinctly the circumstances under which they became separated from theirs. One man, now a Los Angeles police officer, said it happened while he was ''running to save his head," said Roskam.

Another reported stowing the dog tags in a duffel bag before flying home, only to realize later that the bag had never left Vietnam. And a third man, Roskam said, recalled ''coming down a rope from a helicopter when a sniper knocked his helmet off," scattering the tags to the wind.

''A lot of these gentlemen have told me that nobody ever thanked them" for their service, Roskam said. ''This is a chance to say, 'Thank you for what you've done.' "

Recipients have various plans for their recovered tags.

Christine Hopkins, 57, of Coarsegold, Calif., whose then-19-year-old brother, Steven Palmquist, was killed by a sniper while leading a 1968 patrol in Quang Nam, said the family had his returned dog tag put in a shadow box mounted on his mother's wall.

Getting it back, she said, ''was very emotional, but it felt good. It was nice to know that somebody is still out there doing something for all these soldiers . . . in a war that nobody liked. Steven is not forgotten, even after all these years."

Karen Safford, of Essex, Mass., whose 52-year-old brother, Dana, died of a heart attack before his two recovered dog tags could be returned, said the family buried one of them with him and will give the second to his youngest daughter.

And Jack Jones, 55, a veteran from Syracuse, N.Y., said he has worn his tattered dog tag every day since it was returned. ''I have a feeling that it came back to me for some reason," said Jones, who served in Vietnam from 1969 to 1970, ''so I put it on every morning. I just feel that there's something behind it -- I couldn't tell you what. It's a part of my life; it sort of puts closure behind Vietnam."

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