If you ever see the video, it looks awful. The VC prisoner, Captain Nguyen Van Lem (in some sources, his name was Bay Lop) was led up to ARVN General Nguyen Ngoc Loan, who just looked at him. Unfortunately, we cannot see his face as his back was towards the camera. The General then turned towards the prisoner and very nonchalantly waved the pistol back and forth to motion the guards to move away from him. This is when I think his expression must have been scary, because the two guards moved as if they were standing on live electric wires. At this point the prisoner reacted in fear and anger, but he did not have time to do anything else as General Loan simply raised the pistol and fired at point-blank range. He was not even trying to escape, and I don't even think he got a chance to talk. But as I said, because of the circumstances in which he was captured, the General was completely within his rights to do what he did.
Ironically, according to many sources, this was the image that changed the perception of the American public towards the war. It was after the showing of the video oon the 6:00 news that people started to believe tha tUS soldiers should be pulled out and that the US was losing the war.
See
http://en.wikipedia.org/wiki/Nguyen_Ngoc_Loan and
http://www.weeklystandard.com/Content/Public/Articles/000/000/004/666noxlw.asp for more info.
Dean.
http://en.wikipedia.org/wiki/Nguyen_Van_Lem
I found a bit more.
South Vietnamese sources said that Lem commanded a Viet Cong assassination and revenge platoon, which on that day had targeted South Vietnamese National Police officers, or in their stead, the police officers' families; these sources said that Lem was captured near the site of a ditch holding as many as thirty-four bound and shot bodies of police and their relatives, some of whom were the families of General Loan's deputy and close friend. (In some accounts, the deputy was a victim as well; in others, the number of murdered relatives were as few as six.) Photographer Adams confirmed the South Vietnamese account, although he was only present for the execution. Lem's widow confirmed that her husband was a member of the Viet Cong and she did not see him after the Tet Offensive began. Shortly after the execution, a South Vietnamese official who had not been present said that Lem was only a political operative.
Though Loan's execution of Lem would have violated the Geneva Conventions for treatment of prisoners of war had he been wearing a uniform and fighting enemy soldiers, the execution was attributed to war crimes allegedly committed by Lem. The rights of POW status were accorded to Viet Cong only if captured during military operations. Those captured as unlawful combatants were subject only to the laws of the South Vietnamese government, which sanctioned the use of draconian measures.
Note the "had he been wearing..." bit. A bit of diversion there. The fact is that he was not, and the Geneva Convention is very clear on this. If you are a combattant, a member of an organized military force, wearing civilian clothes while fighting in a combat zone, you are considered a spy, with the obvious consequences. In addition, if Lem was only a "political operative", what would he have been doing hiding in a ditch in enemy territory while his death squads were running around?!??
Also keep in mind that the activities of the death squad can be described as war crimes!