They couldn't have gotten away with it
The whole point of gathering these particular ten people together is that each one has committed a murder that the law can't touch. But I have slight problems with these three cases:
General MacArthur: How could he possibly have gotten away with shooting another officer from behind *in his office*, with no one else near them and no incoming fire?
Mr. and Mrs. Rogers: When you hold a pillow over someone's face to smother them, the front teeth leave imprints on the inside of the upper lip. My knowledge of forensic history is a little rusty--I know about when fingerprint technology was first used, but that's about it. So does anyone know if the police would have known to look for this in the 1930s?
Blore: Likewise, I know little about police attitudes in the 1930s, but it would be fairly obvious that Blore killed Landor. Would it have been swept under the rug, or would Blore have been charged?