HANOI, Vietnam -- Two weeks ago, a teen-ager walked into a villa on the outskirts of this capital with a strange tale: In his village, in the northern province of Son La, he had overheard a neighbor telling how he had buried two U.S. pilots who had crashed more than 20 years ago, during the war.
The yellow stucco villa is known to its inhabitants as "The Ranch," and such stories are not unusual there. It is the headquarters in Vietnam of the Joint Task Force-Full Accounting, the branch of the Defense Department that is charged with trying to resolve the fates of more than 2,200 servicemen listed as missing from the Vietnam War.
When the teen-ager arrived at The Ranch, he was interviewed by Vietnamese-speaking U.S. investigator. Less than 14 days later, an excavation team made up of U.S. experts and officials of the Vietnamese defense and interior ministries was at work in the remote village. It has reported finding the "possible remains" of a human in the gravesite.
"This would not have been possible even two years ago," said Lt. Col. Timothy G. Bosse, commander of the task force, marveling at the speed with which the excavation team was shifted from central Vietnam. "We've come a long way."
This high degree of cooperation with Vietnam was cited by President Clinton last week when he announced that he was normalizing relations with Hanoi after 41 years. "With this new relationship, we will be able to make more progress," Mr. Clinton said.
Even with formal relations, however, determining the fate of each missing U.S. serviceman is a Herculean task that could take many years.
Every year, the Americans and the Vietnamese conduct "joint field activities" (JFAs in military parlance), in which teams of U.S. experts -- translators, anthropologists, morticians -- are sent from Hawaii to excavate suspected crash sites or investigate reports about possible sites.
Eight teams made up of a total of 107 U.S. servicemen are in Vietnam for a month of searching, the 36th mission since cooperation with the Vietnamese began in 1986. They are expected to carry out just 12 excavations and 37 investigations.
There are 1,618 U.S. servicemen listed as missing in Vietnam. The remainder are in Cambodia and Laos.
As the Defense Department works its way down the list of reported crashes, the sites seem to become more and more remote, often high in the mountains of central Vietnam.
Of the outstanding cases, about 400 servicemen were reported missing over water, which means that "resolving those cases will be very hard," Colonel Bosse said.
The Pentagon could speed processing of the list of missing servicemen by adopting a new category: remains not recoverable. A decision on that is pending.
All but 55 of the 1,618 listed as missing in Vietnam have been confirmed dead by the Defense Department, but they will remain on the missing list until their bodies are found. The 55 are known as "discrepancy cases" because they were alive when last seen -- after parachuting to safety, for example -- but there is no explanation of what happened to them.
Even with the benefit of a preliminary investigation, following up a crash that happened 25 years ago can be daunting. The teams use window screens to filter dirt, looking for any evidence -- not only bone fragments, but watches, dog tags and scraps of clothing -- that might help establish the death of an American
"If we're off by a couple of feet, we might as well be off by a couple of miles," Colonel Bosse said.
Once remains and effects are recovered, they are handed over to an anthropology team made up of U.S. and Vietnamese experts that determines whether the remains are human and could be American. The remains are then forwarded to U.S. laboratories in Hawaii with full military honors.
There have been 66 positive identifications of U.S. servicemen since the joint task force was established in January 1992, when it took over from the Joint Casualty Resolution Center based in Bangkok, Thailand.
Colonel Bosse, who took over command of the task force last month, said that besides helping on the ground, the Vietnamese are improving the quality of their research into archives that contain information about downed pilots.
"Their reports are much more complete these days. Most questions are answered, and their research is much better," he said.