KOH TANG ISLAND (AP) - After a two-hour helicopter flight from Phnom Penh,

the U.S. military team hits the beach. About six meters from shore, the main rotors

of two helicopters lodged in the ocean floor protrude through the clear blue water.

Other helicopter parts litter the shore.

The team's mission is to close the books on the final U.S. battle of the Indochina

War-the botched May 1975 attempt to rescue crew members of the captured American

freighter Mayaguez.

The investigative team's responsibility is to try to account for the 81 Americans

listed as missing in action in Cambodia, including the 14 Marines who never returned

from the Mayaguez rescue mission.

While there is virtually no hope that any of the missing remain alive, the investigators

hope to find their remains and return them home for burial.

On May 15, 1975-about a month after the fall of Saigon-about 200 Marines stormed

ashore at Koh Tang Island on a mission to rescue the crew of the Mayaguez. The freighter

had been captured by the communist Khmer Rouge after it had mistakenly drifted into

Cambodian waters near the island in the Gulf of Thailand.

Thirty-eight Marines were killed trying to rescue the 39 crew members of the Mayaguez.

Fourteen of their bodies were never recovered during the hasty retreat from the island.

The rescue mission was not only bloody but probably unnecessary. Just a half hour

before the Marines landed on Koh Tang, the official Khmer Rouge radio announced that

the Mayaguez would be released. The White House of then-President Gerald Ford gave

the go ahead for the rescue attempt because the Khmer Rouge had not explicitly said

the crew would be released along with the ship.

To make matters worse, the U.S. military did not know that the Mayaguez's crew were

not on Koh Tang but being held in the port of Kompong Som on the Cambodian mainland.

Instead, the Marines came under heavy fire from a well-entrenched Khmer Rouge force.

The Mayaguez crewmen were all released unharmed.

Seventeen years later, the U.S. investigative team has come to Koh Tang to search

for remains. The island is 225 kilometers southwest of Phnom Penh and 30 kilometers

from the mainland.

During the visit to Koh Tang in early December, some members of the team searched

for a cave where a Cambodian refugee once said some U.S. Marines were buried. Others

dig in a sand berm where the island's only inhabitants-government soldiers-found

two teeth. Still others pick their way among rocks and wade into the water, looking

for remains.

They find two bones along the shore. The day before, they found two more. These,

like all remains, must be sent to a U.S. military laboratory in Honolulu, Hawaii,

for analysis and identification.

Thirty-two U.S. servicemen and servicewomen-representing all four branches of the

military-make up the investigative team in Cambodia. Similar teams are at work in

Vietnam and Laos.

The U.S. Defense Department lists 2,266 Americans as still missing in Indochina-1,658

in Vietnam, 519 in Laos, 81 in Cambodia, and eight in Chinese coastal waters.

The military investigators in Cambodia are fighting time, changes in terrain and

a shortage of witnesses caused by the Khmer Rouge reign of terror between 1975 and

1978. Hundreds of thousands-perhaps millions-of Cambodians were killed or uprooted

and forced into agrarian labor camps far from their home villages.

The U.S. military began its search operation in Cambodia shortly after the Phnom

Penh government and the three rebel factions-including the Khmer Rouge-signed a peace

accord late last year. The investigative team has been in Koh Tang a number of times

since.

"One of the hallmarks of our military has been that we believe very strongly

in going back for our own whether it's five days later, five years later, or 20 years

later," said the Cambodia team leader, Army Capt. Jim Rice.

"It is very important for soldiers to know that they can count on their brothers

in arms to come back for them," he added. "I think most soldiers want to

go home, whether it's alive or dead."

The team prepares for each mission by pouring over countless military records in

the United States that detail the final hours before the military lost touch with

a soldier.

The team comes to Cambodia every two months, spending about 30 days at a time, working

17-hour days, seven days a week.

The team members fly around the country searching for witnesses-often stopping anyone

old enough to remember the war. They conduct painstaking interviews-asking countless

questions through a translator-to establish a supposed witness' credibility.

They scour for clues and, finally, when they have a strong lead as to where a serviceman

may be buried, they excavate the land.

This is dangerous work in Cambodia, where skirmishes continue, fresh mines are laid

regularly, and troops often fire at passing helicopters.

On Koh Tang, the investigative team found a live, 81mm mortar round, which they marked

off with bright orange warning tape.

A permanent office staff in Phnom Penh spends the time between investigative missions

following up the several leads received each day.

Purported witnesses walk in, some hoping for a cash reward. People drop off everything

from helicopter parts discovered at a crash site to rubbings of dog tags to pieces

of flight suits and even bones.

One day the office staff arrived for work and found a cardboard box holding an entire

human skeleton.

Although most leads amount to nothing, the team says it cannot pass any up.

"I don't want to ever be accused of not doing everything I can about resolving

this," said Vietnam War veteran Ed Underwood, a retired Army lieutenant colonel

and a member of the investigative team. "Our sole purpose in life is to resolve

the fates of those cases unresolved."