The Stranger Next Door, Paperback/Peg Kehret

If there s a mystery to be solved, Pete s your man. Er, your cat. Pete s a cat, specifically, Alex s cat. And since Alex and his family moved into a new housing development, Pete is Alex s only friend. Things start looking up for Alex when Rocky moves in next door. But Rocky isn t very friendly, and Alex starts to suspect he s hiding something. And when the neighborhood is terrorized by a rash of fires and vandalism, Pete knows that he s got to investigate."