1.78. A woman has incontrovertible proof in court that her husband was murdered by her sister. The judge declares, "This is the strangest case I've ever seen. Though it's a cut-and-dried case, this woman cannot be punished." (This is different from #1.11.) (MH; from How Come?)
1.78 answer: The sisters are Siamese twins.
1.78a. Variant: A man and his brother are in a bar drinking. They begin to argue (as always) and the brother won't get out of the man's face, shouting and cursing. The man, finally fed up, pulls out a pistol and blows his brother's brains out. He sits down to die.
1.78a answer: They are Siamese twins. In the original story, the argument started when one complained about the other's bad hygiene and bad breath. The shooter bled to death (from his brother's wounds) by the time the police arrived. (RW, based on a 1987 Weekly World News story)