MIA'S; WAR'S UNFINISHED BUSINESS; US: Doing all it can to find missing servicemen?

Among the most anguishing, unresolved issues from the US involvement in the Vietnam war is the fate of some 2,500 Americans listed as prisoners of war or missing in action at the time the United States withdrew from the conflict.

Though the issue remains far from resolved, there have been these recent developments:

* Despite continued denials by the governments of Vietnam and Laos, reports of Americans being held prisoner continue to come from refugees coming out of those countries. And recent photos by US satellites and spy planes are reported to have detected what may have been Americans held in a Laotian compound where what appeared to be the figure "52" had been tramped into the ground. Officials speculate this could be a reference to the American B-52 bomber.

* In July, Vietnam turned over the remains of three more Americans.

* Also in July, and in August, Laotian resistance units cooperating with a private American citizen, turned over the remains of a possible eight Americans. If the remains are identified as Americans, that private citizen, Robert W. Schwab III, will have arranged for the return of the remains of more Americans than has the US government in its efforts to work with the Laotian government.

* And in recent testimony before Congress, the general then in charge of analyzing reports of American prisoners of war (POWs) says that although there still is no proof, he personally thinks some Americans are still being held prisoner in Southeast Asia.

These occurrences raise a basic question: Is the US government doing everything possible to try to verify reports of Americans still being held as POWs and to retrieve remains of Americans from Laos and Vietnam?

Officials at both the Defense Department and State Department insist they are doing everything they can. Assessing the accuracy of this is difficult since officials are not likely to talk about secret efforts if there are any being tried or planned. But there do appear to be increased efforts by the Department of Defense to verify reports of live Americans.

The US track record on POWs and those missing in action (MIAs) since 1973, the year American POWs were returned, is bleak, particularly in regard to Laos.

The US formally recognizes the government of Laos and officially claims no contacts with the resistance groups. Yet the resistance groups are now the only ones willing to seek remains of Americans and information on live Americans. In exchange for desperately needed food, medicine, and clothing, resistance forces could be convinced to help much more, says Schwab, who recently returned from secret contacts with resistance groups in Laos.

While the remains of some 75 Americans have been returned by Vietnam since 1973, remains of only two have been returned from Laos, and none from Cambodia. And the recent, secret US efforts to verify what reportedly were clear spy plane and satellite photos of possible American POWs in a Laotian compound, may have been thwarted in advance by leaks, according to various officials and Schwab. If there are any Americans being held in laos, they could easily have been moved when the mission became known, says a source.

According to the Washington Post, the mission was financed by the US earlier this year after aerial photos showed a compound with people casting shadows longer than cast by most Asians. The marking "52" had been etched in the dirt, apparently by repeated walking in such a configuration, according to a source who has seen the pictures.

But advance word of the secret mission got out, a congressional source says.

"There were leaks all over the place," concurs Ann Griffiths, executive director of the National League of Families of POWS/MIAs in Southeast Asia.

Schwab, a former political and military analyst for the US in Vietnam and one of the last to leave that country, contends the mission was compromised because the US relied on elements among the Laotian resistance forces who "leak" information to the government of Laos (through intermediaries) in order to survive. Only by working with "bona fide resistance Laotian units," he said in a lengthy interview with the Monitor here, could such a mission have been successful. He says that this is how he was able to retrieve remains from the sites of American plane wrecks.

How reliable is Schwab's assessment?

One indication might be the praise for his political assessments in Vietnam, offered by Major Gen. John E. Murray (ret.), former Defense attache in Saigon and for a while the top US military officer in South Vietnam after the cease-fire. Schwab was on General Murray's staff, traveling deep into isolated areas, using his linguistic and analytical skills to develop reports. "I never found him wrong," General Murray told the Monitor.

A State Department official confirms that Schwab is the person who recently turned over remains to the US Embassy in Bangkok.

Schwab says he has made five trips into Laos since 1978 with different resistance units. He says he was not working for the American government in his Laotian efforts, and has not been contacted by the American government for information about the resistance since 1978.

His concern now is that the government of Laos, which remains under the control of Vietnam and is occupied by some 40,000 Vietnamese troops, may be tempted to kill any American prisoners they may have in order to avoid the embarrassment of being found with them by any future US missions.

Efforts by Schwab and a few other private citizens seeking to get information and remains out of Laos by working with the resistance groups have both US officials and the National League of Families concerned.

"The widespread publicity given to the activities of the [Laotian] resistance groups has complicated our efforts to deal with the Laos government," says Barbara Harvey, Laotian desk officer at the State Department.

Private efforts "may interfere" with US secret efforts, says Mrs. Griffiths.

But Mrs. Griffiths credits Schwab with arranging the latest turnover of remains. And Schwab says that in order not to interfere with the US-financed team that went into Laos looking for POWs at the compound where they were thought to be held, he ended his own efforts when requested to do so.

"If anybody can get into some of these areas, it is the Laos resistance," says Mrs. Griffiths. She would like to see contacts with the resistance continued, preferably by the US government. But she addds, "I don't think the State Department has been realistic in their thinking in this issue."

Another strong critic of US efforts is Gladys Brooks, a member of the National League of Families. She has worked steadily to get more information about her son, a Navy flier downed in Laos in 1970.

"I don't know that my son is alive, but I don't know that he is dead," she says. "And I can't rest until I find out."

In recent testimony before a congressional panel, Lt. Gen. Eugene F. Tighe Jr. said some 208 reports are currently under investigation. Other reports had turned out to be "pure hoaxes," or "wholly misinformed," he said. Lt. General Tighe also said 2,497 Americans were still unaccounted for in Southeast Asia.

Asked if he thought some Americans were still being held prisoner, General Tighe told the panel there was no proof. Then, asked for his personal view, he said yes.