1. 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."
2. A man and his wife raced through the streets. They stopped, and the husband got out of the car. When he came back, his wife was dead, and there was a stranger in the car.
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Solution number 1.: The sisters are Siamese twins.
Solution for number 2.: The wife was about to have a baby. They drove to the hospital. The husband left to get a wheelchair, but the baby was born in the meantime, and the wife didn't survive the birth.