It was the first day of school when a young girl was found dead in the classroom. Police had identified four suspects.
The Dean claimed that he was in his office the whole day. The Maths teacher claimed that she was giving the midterm exam results to her students. The clerk claimed that he was bringing the mails. The janitor claimed that he was cleaning the toilet on the first floor.
Who was lying?
The Maths teacher was lying. She cannot be giving the midterm exam results on the first day of school.