Conspiracy theories about US servicemen missing since the Vietnam war still abound, and there are numerous websites devoted to exchanging details about alleged sightings.
Global Spy magazine says on its website that an Arizona teacher was told by Vietnamese officials that missing US soldiers were being held and would be released only if the embargo then in force against the war-ravaged country was lifted.
The site advertises a video, A Nation Betrayed, featuring Colonel James "Bo" Gritz, described as a decorated Vietnam war hero.
He claimed to have returned from Indochina with evidence of up to 47 missing Americans being held at one camp, though little information in is given in support of the claim.
Some of the conspiracy theories suggest dark political machinations.
A 1991 copy of a little known fringe magazine called Spotlight said: "Because of a desire to exploit the oil reserves of Indochina, the United States is trying to cover up the issue of live PoWs until they are all killed next January or February, the Senate was told November 7.
"This charge was made before the Senate select committee on PoW/MIA affairs by Hamilton Gayden, a circuit court judge in Tennessee, who has written a book on the subject.
"Gayden has long been active in efforts to bring home hundreds of the 2,000 missing men who, extensive evidence shows, are still alive.
"Government bureaucrats fear 'the ever-present threat that the Vietnamese and Laotian leaders will disclose to the American people the existence of live Americans who still want to be repatriated', Gayden said.
"'The government is determined to declare all missing men dead because of the intense outrage that would result if the American public learned of their abandonment,' Gayden said.
Those Americans nurtured on Rambo films who believe their government is lying to them took further heart when the former US presidential candidate Ross Perot claimed that information about PoWs who might still be alive was suppressed.
The Vietnamese themselves are not immune to rumour and conjecture. An organisation in Hanoi snappily known as the Science Technology Union for Informatics Application coordinates the services of psychics who claim that they can help bereaved relatives communicate with some of the country's missing 300,000 soldiers.
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