The Smith family is a very wealthy family that lives in a big, circular home. One morning, Mr. Smith woke up and found his gardener's body. He knew it was one of his employees who had killed him. So he asked them what they were doing in the morning and he got these replies.
Driver: "I was outside washing the car."
Maid: "I was dusting the corners of the house."
Cook: "I was starting to make lunch for later."
From the replies he knew who the killer was. Can you guess who it was?
The maid, because they lived in a circular house and she was apparently "dusting the corners" of the house at the time of the murder - the house is round, therefore it has no corners.