In the middle of the maelstrom of World War I, The General could have ordered his men "over the top," then tossed/moved the body of the Lieutenant nearest the action. With the huge number of corpses piling up, who is going to suspect murder? Even if murder is suspected, how can ordinary medics deduce that the victim was shot "back to front" instead of "front to back"? Rank has it's privileges, so who would question, let alone suspect a senior officer of a low grade crime in war? As for the Detective Sergeant, this is another case of Authority triumphing over Justice. He could hang the "active interrogation" results on another squad of Constables or say that "Short Eyes" got it from unruly prisoners. Mass murderers escape justice every day...

Yes, it could have happened that way, but it doesn't really fit the story. Most of the others were guilty of abusing authority -- the governess let her child go into danger, the old lady bullied a depressed, frightened girl, the doctor did an operation while drunk, the caretakers killed a patient entrusted to their care. To say that Blore and the general committed murder and covered it up sounds like it was imported from another Christie story.

I haven't read the novel, but it seems like the original murders are better than the show's... Although the show wasn't bad at all..