In one of his letters, Hemingway talks about how he shot a German prisoner of war after unsuccessfully interrogating him:
"One time I killed a very snotty SS kraut who, when I told him I would kill him unless he revealed what his escape route signs were said: You will not kill me, the kraut stated. Because you are afraid to and because you are a race of mongrel degenerates. Besides it is against the Geneva Convention.
What a mistake you made, brother, I told him and shot him three times in the belly fast and then, when he went down on his knees, shot him on the topisde so his brains came out of his mouth or I guess it was his nose.
The next SS I interrogated talked wonderfully."
[Ernest Hemingway, Selected Letters 1917-1961, ed. Carlos Baker, New York 1981; p. 672.]