In Vietnam, as a tank driver, I remember some action near the Cambodian border in an area we called The Elephant Ear because on a map, it resembled an elephant ear.
It was a quick combat skirmish where we were fired upon and our tank fired a canister round in the area it came from. Slowly moving up with infantry we came across three bodies. I could see through my forward scope two bodies that were obviously dead and one seemed to be just laying on the ground sleeping.

I remember the grunts slowly moving up and one, as he approached the prone body gave two quick shots at it, glanced at it, yelled something to the soldier near him, and kept walking. I remember this clearly, not because he gave the body a double tap, which to me meant he was just playing it safe, but this soldier had a large black spade, like from a playing card, on the back of his flak vest. The spade meant ill fortune and death to the Vietnamese apparently. I saw it on tanks and ACAVS also.

We had heard that a trick of the VC was to lie and play dead until US soldiers had passed then either shoot them in the back or throw a grenade then dash into the jungle and suddenly disappear. I never saw it because I don’t think a VC would do that in front of a tank coming toward him but I heard it did happen.

I think it is illegal if you pass a body, then turn and shoot it however, if the body is in front of you, to shoot it is not illegal. In combat there’s no way of knowing if that body lying prone is dead or pretending. You do not want him to rise up and shoot or stab you in the back. In front lines in combat, it’s done all the time.