 2nd Battalion , 9th Marines landed on Koh Tang Island where the crew of the SS Mayaguez was believed to be held , they were unaware that the crew was already in American hands . The Marines and the CH @-@ 53 helicopters which transported them , were attacked by the Khmer Rouge with machine guns , mortars , and rocket propelled grenade launchers in what became known as the Battle of Koh Tang Island . When the battalion received word of the safe arrival of the Mayaguez crew on the USS Wilson the Marines planned their withdrawal once they received orders from the U.S. Joint Chiefs of Staff to that effect . After the last helicopter left , a head count showed that 3 Marines were left behind on the island . They were : <unk> Gary Hall , <unk> . Joseph <unk> , and <unk> Danny Marshall from E CO , 2nd Battalion , 9th Marines . The three Marines were captured by the Khmer Rouge within a few days , tortured , executed , and buried in a common , unmarked grave on Koh Tang Island . 
