A man is found dead with a knife wound to the chest in a round house. Police investigation was narrowed down the suspect to three people: The wife, the maid, and the slayer. When questioned for defenses,
The wife said, “I was out for shopping with my friends, and I found my husband dead upon my return.”
The maid said, “I was in the other room, dusting the corners.”
The slayer said, “I was searching the cupboards for some vegetables to serve for lunch.”
The maid was then arrested. How did the police know ?