A rich man who lived in a large mansion is found murdered on a Sunday morning. His distraught wife called the police, who questioned her and the house staff. They gave the police the following alibis:
The wife said she was sleeping.
The butler was cleaning the closets.
The gardener was weeding the garden.
The maid was getting the mail.
The cook was preparing breakfast.
The police arrested the murderer immediately. Who did it and how did they know?