Fredericksburg, Virginia. Just before noon each day in 1969, I'd slip behind the wheel of my car in Danang, South Vietnam, and head through the shady streets for lunch at a local restaurant. It was a daily routine for me, a 23-year-old spy handler with Army Intelligence: I was a novice operator in the shadow wars of Vietnam.
Along the way I'd look for a white chalk mark on a certain wall, a secret ''load signal'' from my agent that he had reports to deliver.
A pock-faced Vietnamese businessman twice my age who had been spying for the French and Chinese long before hooking up with us, the agent usually left his mark two or three times a week. Later, I'd head to a beach where a boy peddling ice cream would come along and hand me the reports, written on thin paper wrapped around an ice cream cone.
Usually they were humdrum fare, a few paragraphs on communist combat units sent in by a net of woodcutters, soup vendors and small-time merchants recruited to spy for us. But the reports were usually quite accurate, if only because by mid-1969, most enemy units had been operating in the same area for years.
One day the pattern began to change, a development that goes a long way toward explaining why the POW-MIA question, which flared again last month, is not likely ever to be satisfactorily resolved.
It began with the Phoenix Program, a CIA-run operation to find and ''neutralize'' secret agents of the communist underground. Over a series of meetings in hotel rooms in Danang I explained the new program to my agent, who was eager to get on with it. Soon his spies were supplementing their reports with detailed narratives on local communist agents. The leader of a women's federation was uncovered, as was a communist agent in a farmer's union. Most reports, however, had begun to focus on an anti-war Buddhist sect. The net surged with accusations that the religious group was a communist front.
One unforgettable day, our whole enterprise was cast into doubt. During a routine polygraph examination my agent flunked a question on whether he was loyal to the Saigon government.
Stunned, we asked him whether he was a communist agent.
''No.'' A sympathizer? No, again. Each time the machine indicated he was telling the truth. In short, the machine told us he was not loyal to his own government, but he was not a Viet Cong mole either. We were stumped.
Finally, we found the key that not only unlocked the mystery, but helps explain why today's ''intelligence'' on POWs is likely to be found so unreliable.
My agent, it turned out, was not a communist. He was, however, a member of the Vietnamese Nationalist Party, a right-wing group plotting against the Saigon government. This group had targeted the anti-war Buddhists as their principal political enemy -- the same people our agent had named as Viet Cong for the Phoenix program.
Was he using us against his enemies? Probably. I recommended he be fired, but unfortunately the heavy flow of his information, no matter how suspect, was deemed too valuable to lose.
It's not a unique tale. I heard lots of horror stories about unreliable agents and ghost payrolls. (One friend nicknamed his net ''Ali Baba and the 40 Thieves'' for all the money they stole.)
The point is that we had few real spying successes during our time in Vietnam, despite our thousands of agents and tons of captured documents. So there's little reason to think that the ''live-sighting'' reports on POWs are any more valid now than they were when we were in a much better position to gather reliable information. For now, as during the war, our intelligence reports are compromised by the fact that every Vietnamese knows what we're looking for -- and is eager to sell it to us.
* * * The Final Report of the U.S. Senate Select Committee on POW/MIA Affairs has plenty of evidence that we are chasing POW ghosts in Vietnam. Last year a team of two American investigators and one Hanoi official, acting on a tip from a Vietnamese exile in Tacoma, Washington, tried to track down a ''William George Morgan,'' said to be living in the Central Highlands of Vietnam. The exile said he had heard about ''Morgan'' from someone in Saigon.
The team found the original source, a Mr. Toan, at his coffee house in Saigon. He said he had no personal information about ''Morgan,'' but offered to lead them to someone who did. ''He also produced three bundles of human remains (bones and skulls),'' the committee noted, ''which appeared to be Mongoloid rather than Caucasian.''
They all drove 90 miles to Xuan Loc, where they found a Mr. Bao, who also had no information on ''Morgan'' but offered to take them to someone who really did. ''Mr. Bao also offered three bundles of bones which also upon casual inspection turned out to be Mongoloid,'' the team noted.