Enid Blyton 
Mystery of the Disappearing Cat 
Five Find-Outers #2

When Pip’s neighbour’s cat is stolen, the Five Find-Outers new friend, Luke, is blamed for the theft. Unfortunately, there are no clues, and Luke is the only suspect. Can the Find-Outers protect him from the law and solve the mystery? This is the second adventure of the Five Find-Outers and Buster, their dog.