When Mohammed, 29, a Vietnamese of the Cham Moslem minority, fled his homeland in 1981 with his wife and two children, he expected to be able to go to the United States. He thought he had a good case: from 1972 to 1975 he had worked for Air America, the CIA airline during the Vietnam War, and his wife's sister had already gone to the United States as a refugee.

But after making a hazardous trip across Vietnamese-occupied Cambodia to the Thai border, Mohammed and his family became caught up in Thailand's "humane deterrence" policy aimed at discouraging refugee arrivals by declaring them ineligible for resettlement abroad.

Mohammed and family ended up at NW82, an overcrowded detention camp dangerously located amid a sprawling Cambodian refugee settlement on the Thai-Cambodian border.

Then last month Thailand softened its policy and began allowing western officials to screen the nearly 1,900 NW82 inmates for immigration. Mohammed was given new hope. But it was soon dashed.

An official of the U.S. Immigration and Naturalization Service (INS) rejected Mohammed's refugee application, although a U.S. Embassy official in Bangkok confirmed he had been an Air America employe and he had said he left Vietnam for "fear of trouble if the government found out I worked for Air America."

In explaining his rejection, the INS officer wrote, "I have no reason to doubt that this man worked for Air America, but I don't see that he was persecuted for that reason or any other reason."

No questions were asked during the interview about persecution on religious or ethnic grounds, although State Department reports say the Vietnamese Communists have suppressed the religious activities of the Cham Moslems. Nor did it seem to matter that Mohammed said he had escaped from a reeducation camp in June 1975 after serving for a month.

Mohammed's case is one of hundreds that have surprised and dismayed western refugee officials, who have been pressing for more than a year to get the Vietnamese "land people" out of Camp NW82 and away from the volatile border. Thai authorities have said they plan to close the camp when the United States and other western resettlement countries take all the eligible applicants. Those left behind will then have to remain on the border amid the often hostile Cambodians.

"In many cases that's going to be a sentence in itself," one refugee official said. "Some are going to die, and some are going to undergo multiple rapes--again."

Such are the stakes in the latest skirmish of the long-running feud between the INS and the State Department over who is a refugee. The dispute stems from some INS officials' seeming dislike of the refugee program and, through it, the State Department's involvement in immigration affairs.

The State Department won the last round in mid-November when Thai authorities strongly protested that INS processing of Cambodian refugees at the Kamput camp in southeastern Thailand was going much too slowly, and Attorney General William French Smith sent in a 14-member team to take over the task from Bangkok's four permanently assigned INS officers.

The result was that the approval rate for applicants rose from 20 percent to 80 percent, and 12,000 refugees went to the United States.

Now, however, western refugee officials hold out little hope that what they regard as an unfairly high INS rejection rate at NW82 can be reversed.

Up to Saturday, INS officials screening refugees at NW82 have accepted 494 and rejected 336, according to the latest statistics from the camp. Those screened include 225 Vietnamese with "close family relations" in the United States--parents, children, spouses or unmarried siblings. Of these, 119, or 53 percent, have been rejected.

According to U.S. and other western refugee officials familiar with the screening, the problem stems from the INS officers' strict definition of refugee status based on a "well-founded fear of persecution" in the home country. The irony, the sources said, is that many of these Vietnamese might be eligible for resettlement in the United States if they were applying as ordinary immigrants, but their U.S. family ties are working against them because they are being processed as refugees.

"Every other country in the world except ours has provisions for family reunification" of refugees, said one U.S. official. But in the case of NW82, "family relations in the U.S. is a strike against you. It's no exaggeration to say that some Vietnamese are being denied entry into the U.S. because they have close family relations there."

The INS rationale is that the reason for leaving Vietnam was to join relatives, not a fear of persecution, the refugee officials said. No Bangkok-based INS officers were available for comment.

In Washington, INS spokesman Verne Jervis said Monday that the approval rate for Vietnamese refugees in Thailand to come to the United States is "about 75 percent" and that the decisions, taken case-by-case, are based "on the law and the guidelines."

"We work closely with the State Department for information on conditions relating to persecution in the individual countries," he said, adding that the 1980 Refugee Act incorporates the U.N. definition of refugees "so we adhere to an international standard.

["The U.S. commitment to a generous refugee program is indicated by the numbers available--64,000 for Asians in this fiscal year out of a total refugee ceiling of 90,000," he said.]

State Department officials have long argued that even if a Vietnamese may not have had a "well-founded fear of persecution" before he left, he would face such treatment if he went back to Vietnam.

The problem has another aspect, described by one European refugee official as "pure Catch-22."

That is, "once a fellow is turned down by the U.S. and has family there, he's not of interest to other countries," the official said. "This leaves the fellow in a worse situation than if he hadn't said he has family in the U.S. The fact that he's got family in the States puts him out of court for everybody else."

Among the other countries processing the Vietnamese at NW82 for immigration are Canada, Australia, Finland, Denmark, Italy and Sweden. Although they have no history of involvement in Vietnam, some of these countries are taking the more difficult cases such as handicapped persons and unaccompanied minors.

Son, a 30-year-old of Khmer Krom ethnic origin, was turned down although he is known to have served for five years in Phnom Penh with the Special Investigations Unit of the Cambodian National Police Force before the Communist takeover in 1975. The INS report on his interview, nevertheless, described him as having "no close association to the U.S. or the pre-[19] 75 government."