I've just read your message. You talk about a L/317th Inf. veteran who was taken prisoner by the German in the Falaise Gap. As far as I am concerned, the story of this veteran is really interesting. Because I have two reports and one civilian account which deal with the same fact : during the battle for Argentan, 80 GIs, from both 317th and 318th Infantry Regiments (80th Division), 80 men from these units were captured by the Germans, around August 17th-18th, 1944. They took them in the Gouffern Forest. When the German made their attempts to break through the US lines near Chambois (the 90th Inf Div was there), they forced the prisoners to climb up on the German vehicles, believing that if the others GIs from the 90th see the prisoners they would not open fire but actually, they did and they probably didn't notice there were American soldiers. 50 prisoners were killed, only 30 were liberated by the 90th Div. men in Chambois, about noon on 20th Aug.
'Your' veteran was probably one of the 30. I can give more details if you are interested.