Who is Lying ?

The Smith family is a very wealthy family that lives in a big, circular home.
One morning, Mr. Smith woke up and saw a strawberry jam stain on his new carpet.
He figured out that everyone who was there that morning had a jam sandwich.
By reading the following excuses, figure out who spilled the jam.
Billy Smith: �I was outside playing basketball.�
The Maid: �I was dusting the corners of the house