... because you are always being lied to.
"No honestly doc I eat nothing but vegetables! I have no idea why my cholesterol is 500!"
"My wife was very depressed. It's no wonder she shot herself nine time in the face."
And so on.
This is the story of the murder of soldier Vincent Goslyn Jr. who died on a remote road in Kentucky near Fort Campbell, where he was stationed when not deployed. He had been shot repeatedly at point blank range, and according to his wife he had told her to make a run for it. So she drove away in her truck and called police. She was hysterical when they found her, but she eventually pulled herself together and told police that her husband tried to help a stranded motorist, who got into an altercation with Vincent and killed him. She accused a black man she did not know in a big old rust colored car.
But there was another witness. He didn't actually SEE the shooting, but heard the shots. He said there was nothing unusual about the sound of gunshots in this remote area, but said he then walked out and found Vincent dead on the side of the road and a white truck driving away, not an old rust colored car. And the investigators take it from there.
This would have made a great film noir. It has everything - drug dealers, love triangles, greed, legal technicalities, and lying. Lots of lying. And of course, in the end, thieves fall out. One thing you would likely NOT have in a film noir of the 40s and 50s? The accusation of the lone nut who does not know you but somehow has it in for you just because you are part of the human race. That was rare before the 60s when running into somebody like Charles Manson and company became our collective American worst nightmare.
This is a pretty good episode of Dateline, and I'd recommend it.