I knew a man who had a box full of photos from the Bataan Death March. I accidently found them in a shoe box while looking for something else for him in his study. The photos were taken by the Japanese and were horrid. He would not explain how he got them and refused to talk about them or the war. The gentleman has been dead for many years now. Whenever I hear about the death march I think of him and wonder....
Good Lord, you may have discovered another primary source of information! Check with the man's survivors and question them about those historical photographs. They need to be compared against archived ones to see if they are perhaps unique.