Aalia's kidnapping - Detective Riddle

On the first day of school, Aalia was kidnapped. Police suspect three 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.

The police arrested the kidnapper. How did the police find the kidnapper?

• Mr Walter
• Mr Thomas
• Mr Benjamin
• none of these

Mr Thomas