Riddle: On the first day of school, a young girl was found murdered. Police suspect four male teachers and question them. They were asked what they were doing at 8:00 am. Mr. Walter: I was driving to school and I was late. Mr. Thomas: I was checking English exam papers. Mr. Benjamin: I was reading the newspaper. Mr. Calvin: I was with my wife in my office. The police arrested the killer. How did the police find the murderer?
Answer: Mr.Thomas as he cannot be checking exam papers on the first day of school.