CBS News investigates what happened to three American troops left behind alive on Koh Tang Island in the last battle of America's war in Southeast Asia. The mission of the Marines who fought the battle was to save the crew of the SS Mayaguez, a merchant ship seized by the Cambodians. "For decades the mission was hailed as a victory. In truth, it was a military disaster in which bad intelligence cost American lives," the segment reveals. Other findings include that the government knew the three Marines left behind were alive; that the men could have been saved for days, possibly weeks, before being captured and executed; and that their families were told that the troops died in combat.