The 2nd Bn, 1st Marines Command Chronology for Nov 1966 contains the following entry for 20 Nov:
At 1415 hours, a Company F platoon conducting a combat patrol at BT 040602 (Highway QL1, 1 kilometer N or Thu Bon River and 3
kilometers NorthWest of Dien Ban) discovered a mined punji trap. During the probe of the pit, the mine detonated causing 3
USMC Killed in Action (KIA) and 8 Marines Wounded in Action (WIAs) of which 3 WIAs were not evacuated.
The three men killed by the mine were