Hard situation puzzles

A coin collector finds an internet advertisement about a coin collection at a very low price. After reading it carefully, he decides to buy it. Although it is genuine and its value is much higher than the price he pays, he is not happy but very angry.

A woman starves to death despite being surrounded by food.

A woman misread something and never saw another person again.

A person called the police and told them to ask about John K. Upon arrival at John’s house, the police found him dead. Examining the corpse, the police discovered severe injuries. But the apartment was in perfect order, without any signs of a struggle or break-in.