The Mayaguez incident sparked the last battle of the Vietnam war. It occurred on a remote Cambodian island
Memories of the final days of the Vietnam War are often triggered by infamous photographs of the hectic evacuation of the U.S. embassy in Saigon, a day before South Vietnam’s surrender in late April 1975. The image of a North Vietnamese tank crashing through the wrought-iron gate of Independence Palace is symbolic of the end to U.S. military presence in the region.
Yet it was on a small, rock-fringed Cambodian island that the Americans fought their final mishandled battle of the generation-defining war.
Some 50 kilometres off the coast of Sihanoukville sits tiny Koh Tang, its coral-sand beaches bloodstained from the offensive presence of the Khmer Rouge militias that once patrolled it.
The isle’s rarely used English name, Legend Island, suits the stories that followed the Mayaguez incident, the only ground combat between U.S. forces and the Khmer Rouge. It took place on Koh Tang from 12 to 15 May 1975, a mere two weeks after the fall of Saigon, following the capture of an American merchant vessel in disputed waters.
Nearly five decades later, the 18 U.S. servicemen presumed to have died on Koh Tang – three of whose remains have never been recovered – have become an unfinished priority for a U.S. agency dedicated to that task. Three of the 18 were left behind following the battle. Finding them, and another 30 American soldiers lost in Cambodia during the spillover from the war in Vietnam, has fallen to the Defense POW/MIA Accounting Agency (DPAA).
As a division of the U.S. Department of Defense, the DPAA is responsible for recovering and identifying missing military personnel, including all soldiers lost in major American conflicts since World War II. “But the mission goes back towards the end of the Vietnam War,” said the DPAA’s Chris Williamson.
The agency’s resident expert on the Mayaguez incident, Williamson is a generation too young to recall the actual affair. His first trip to Koh Tang, he said, was a recovery mission in 2000. “I knew nothing about the history of the battle,” he confessed. “Most people know about the Tet Offensive or the Easter Offensive, but Koh Tang is one of those fringe incidents – either you know about it or you’ve never heard of it.”
Now, as lead analyst for the remaining three cases of unaccounted-for U.S. personnel on Koh Tang, Williamson has spoken to veterans of the Mayaguez incident and is writing a master’s thesis about the battle.
The U.S. Ambassador to Cambodia, Patrick Murphy, told Focus Cambodia that he has twice discussed the Koh Tang cases with Prime Minister Hun Manet since Manet took office in August.
The fates of nearly 1,600 American soldiers in Vietnam remain unknown. Hundreds are designated “non-recoverable,” meaning that despite rigorous investigations, the DPAA believes they perished but their remains are not recoverable. In Cambodia, two of 48 cases have been placed in the non-recoverable category.
“As the war was progressing and we started to lose pilots, the (North) Vietnamese were not very forthcoming with information on who they were holding, who was alive, and which ones were prisoners,” Williamson said. ”Families in the U.S. were asking lots of questions about that.”
On Koh Tang, 13 of the 18 servicemen who went missing in action on the island have been identified and recovered.
What happened on Koh Tang?
The story of what happened to the last three Marines known alive at Koh Tang has been at the forefront of DPAA investigations in Cambodia.
On the afternoon of 12 May, Khmer Rouge soldiers captured the merchant vessel SS Mayaguez and its crew near Poulo Wai, a pair of tiny uninhabited isles in disputed waters beyond Koh Tang. In its cargo, the ship en route to Thailand from Hong Kong, was carrying materials from the former U.S. Embassy in Saigon, evacuated a month earlier. (In preceding weeks, the Khmer Rouge navy had seized several foreign vessels in the same area.)
The crew of the Mayaguez broadcast a mayday following their engagement with Khmer Rouge swift boats. U.S. Marines came to their rescue only to discover that American intelligence was faulty. Although U.S. Navy flyovers indicated the Mayaguez crew had been evacuated toward the Cambodian mainland, and the ship left anchored off Koh Tang, U.S. President Gerald Ford launched a rescue mission in the belief that the crew was being held on Koh Tang. Marines ordered to storm the island were told to expect 20 to 40 ill-equipped adversaries, not the 200-odd, hardened Khmer Rouge soldiers whom they encountered.
Early in the morning of May 15, eight U.S. helicopters (in two waves of four) swooped towards Koh Tang, intending to drop Marines on the island. Khmer Rouge soldiers quickly shot two from the sky, killing most of the crewmen; survivors either made their way to the treeline or swam to sea under withering fire from a rescue craft. The other choppers fared only slightly better: One made an emergency landing on the Thai coast, while another limped out to sea where it crashed, killing another airman.
By afternoon, more than 200 Marines had landed on Koh Tang, even though the Mayaguez and its crew were now safely aboard an American destroyer, having been rescued by a Thai fishing boat. As darkness set, the Khmer Rouge relentlessly attacked a now-stranded Marine contingent as a crippled fleet of U.S. helicopters engineered a withdrawal. But three Marine machine gunners – Private Danny Marshall, Private First Class Gary Hall and Lance Corporal Joseph Hargrove – never made it aboard the last helicopter and were left behind in the hectic withdrawal from the island.
While President Ford hailed the mission as a resounding success and a crisis averted, details about the final moments of Hargrove, Hall and Marshall remained a mystery. The Marines’ disappearance became a contentious issue, with families demanding answers and details arising of a Navy SEAL team being forbidden to orchestrate a rescue mission by their superiors.
Following the trail of evidence
Since the 1990s, the DPAA has visited Koh Tang alongside U.S. and Khmer Rouge soldiers who fought in the battle, to help identify Hargrove, Hall and Marshall. Publicly disclosed accounts from Khmer Rouge soldiers suggest the Marines were captured, executed and buried either on the island or at a prison camp on the mainland.
While DPAA missions to locate the Marines are ongoing, one Cambodian source suggested that a body found by the DPAA in 2008, near a mango tree on the island, might be American, disputing DPAA claims at the time.
In 2016, the DPAA also found Hall’s ID card and items in an empty burial pit on Koh Tang. The agency withheld details about an American radio and Marine flak jacket suspected to have a name and ID number on it, which they later admitted to discarding.
After the initial interview with Focus Cambodia, Williamson looked into the case more. “At last one flak vest was recovered in 2008 and may have had a name associated with it, but it appears to have been tied to one of the other loss incidents,” he said.
“I did hear something about body armour, but I don’t remember hearing about names or numbers,” he said. “Part of the problem is even if there were a serial number on the equipment, the respective services often did not maintain records of who they were assigned to, so if they don’t know, we wouldn’t either.”
Willamson said he is unfamiliar with the recovery of a radio. But when he attended the 2018 Koh Tang Veterans reunion, he asked some of the Marines if the three stranded Marines had radios.
“Only some of the key personnel carried radios and had call signs during the battle,” Williamson said. “But these guys were a machine gun team: no radios, no call signs and no real training (if any) in their use. So finding a radio on the island doesn’t connect to any of the missing personnel, except that someone might have come across equipment that was left or lost in the battle,” he said.
Yet former Air Force Staff Sergeant Robert Velie claimed that as the last helicopter was leaving Koh Tang island, he received a radio transmission from one of the missing Marines, asking when the next chopper was coming back for them. Velie and his team were coordinating the battle from aboard the EC-130E Airborne Battlefield Command and Control Center. Initially thinking it might be a trick, Velie requested an authentication code, and the Marine provided the correct response.
Reuniting family members
Now, nearly 49 years after the Vietnam War ended, the DPAA mostly operates with picks and spades, determining where to dig for remains with intelligence gathered from researchers, witnesses and officials of the Vietnamese, Cambodian and Laotian governments.
Any found remains deemed to be those of U.S. soldiers – or in some cases, foreign journalists – are transferred to DPAA’s laboratories in Hawaii or Nebraska for further analysis and identification by forensic anthropologists. If identified, the remains are then returned to the deceased’s family, Wiliamson said.
U.S. Ambassador Murphy told Focus Cambodia that another DPAA visit to Koh Tang is planned in the spring of 2024. Williamson concurred.
A possible obstacle was a memorandum of understanding for a $1 billion resort development on Koh Tang, signed in 2016, that could have put all future missions to the island in jeopardy.
“We understand that as of 2020 or 2021, both investors pulled out of the plan for one reason or another,” said Williamson. “We haven’t heard anything further about the possibility of development in the last few years.”
The DPAA has attempted to make contact with tour diving operators in the area, hoping they will notify the agency if they come across the sunken CH-53 off Koh Tang’s west beach, according to Williamson.