Amelia's teacher called her in one day and told her that she was really proud of her because when a student fell and hurt her knee, she was the only one that wasn't laughing. However, when Amelia replied back to her teacher, she said she would've laughed if she could've. Why didn't she laugh?
Answer:
It was Amelia herself that fell and hurt her knee.
She killed her sister in hopes that the man would be at the funeral. Some people say this riddle is a test of a psychopath. If you answer it correctly, you could be one.